For once that was an ideal. And a goal. To be 'restored'. By racial breeding and struggle. And it was readily apparent to really everyone that not every German was blonde.
That said, Hitler himself was not a "perfect example", but he also wasn't the complete opposite of that concept either, as he had blue eyes:
And was also with 175cm quite average in height (Goebbels was only 165 and the average height of German males born around 1890 was 168.6cm):
Left: 1935, left-to-right, Werner von Fritsch, Werner von Blomberg, that man; via src / Right: Hochverratsprozeß gegen die Teilnehmer am Münchener Putsch vom 9. Nov. 1923; München 1924
Furthermore the equation Germans=Aryans is not what was proclaimed to be the case in the first place:
To which race do Europe’s peoples belong?
The peoples of Europe do not belong to a particular race, but are rather a racial mixture. Our German people is comprised primarily of six races.
And what are they?
The Nordic, the Pfalzish (fälische), the Western (westliche) the East Baltic (ostbaltische), the Ostic (ostische), and the Dinarish (dinarische) races.
The German people is, along with the English, Danish, Norwegian, and Swedish, the most racially pure of the European peoples. With regards to the purity of language, the Scandinavian peoples are in first place.
Werner May, Deutscher National-Katechismus 2nd edition (Breslau: Verlag von Heinrich Handel, 1934), pp22–26.
— Quoted here: The German National Catechism)
And within this 'system' Hitler may be grouped into x% Nordic, y% Dinaric or Ostisch (alpine) and some other colours. That is Southern branch Aryan mainly, not pure, not ideal, but OK (p121). And bein' a Führer should clearly indicate that the Nordic component is, well, "dominant"?
His academic lackeys, like Ernst Günther Gründel (Die Sendung der jungen Generation. Versuch einer umfassenden revolutionären Sinndeutung der Krise, 1932, p293) or Gerhard Mackenroth (jstor) come to a similar conclusion:
The great drummer, creator and organizer of the movement, Adolf Hitler, could be a Nordic-Eastern-Dinaric mixture (not purely Dinaric, as opponents have claimed)".
— (Gründel, my translation)
And of course, if 'needed', that system was flexible enough to dismiss the 'science' altogether and allow the adage being ascribed to Göring: "Who is Aryan/Jew is what I decide!"
Q Did they ever address this?
Sometimes they did.
During his table-talks Hitler is said to have mentioned that for example among ancient Germans it was known that already among the Goths they were known to have non-blondes as well.
The man allegedly said this:
Wir alle leiden am Siechtum des gemischten, verdorbenen Blutes. Wie können wir uns reinigen und sühnen? … Das ewige Leben, daß der Gral verleiht, gilt nur den wirklich Reinen, Adligen!" (src)
We all suffer from the infirmity of mixed, corrupt blood. How can we purify and atone for ourselves? … The eternal life which the Grail bestows is only for the truly pure, nobles!
The director of the "Institute for Knowledge of the Human Kind" (his own private invention) wrote like a theoretical mathematician:
Den Gedanken, daß Hitler ein Ausländer ist und von der gegnerischen Presse jahrelang als Ausländer beschrieben und in gemeinst verfälschten Bildern gezeigt wurde, möchte ich somit restlos beseitigt haben. Hitler ist blond, hat rosige Haut, ist also rein (arisch-) germanischer Natur, und alle anderen Verbreitungen über sein Aussehen und seine Persönlichkeit hat die schwarze und rote Presse in die Volksseele gesät, was ich hiermit
richtiggestellt haben möchte.
The idea that Hitler was a foreigner and that for years the opposing press had described him as a foreigner and shown him in meanly falsified pictures, I would like to have thus completely eliminated. Hitler is blonde, has rosy skin, is thus pure (Aryan) Germanic in nature, and all other propaganda about his appearance and personality has been sown into the soul of the people by the black and red press, which I would like to have corrected here.
— Tobias Ronge: "Das Bild des Herrschers in Malerei und Grafik des Nationalsozialismus: eine Untersuchung zur Ikonografie von Führer- und Funktionärsbildern im Dritten Reich", LIT: Münster, 2010, p242.
See, that was easy.
Problem solved by scientist.
More general information on the 'exact' definitions (they are all incongruent and convoluted, with competing theories that cannot be reconciled) a nazi centric starting point would be Hans F. K. Günther who wrote Rassenkunde des deutschen Volkes.
Q Did anyone else ever bring it up or point a finger about it?
Others did that offensively.
A well known political whisper joke during the 1930s was
"Wie sieht ein echter Arier aus? –– Blond wie Hitler, groß wie Goebbels und schlank wie Göring und keusch wie Röhm!
What does the ideal Aryan look like? –– Blond like Hitler, tall like Goebbels, slim like Göring and chaste like Röhm.
This German joke was then picked up for propaganda by "others":
Found by @njuffa:
A slightly different version of the joke was used in the American short film "Don't Be A Sucker" from 1943
That his enemies within his own party have started the rumours might not surprise anyone who expects severe infighting in a still tiny political club of disenfranchised haters in 1921. But these allegations of outright Jewish descent for Hitler himself didn't bother the man until his nephew wrote about that rumor to him in a letter in 1930. Hans Frank was tasked by him immediately to evaluate that allegation and came up empty handed. But in 1942 Himmler took up that line, failing likewise, as one of Hitler's grandfathers is just unknown. In the meantime the propaganda abroad picked up the existence of a Jewish gravestone in Bucharest with the name of "Adolf Hittler" on it, drawing far ranging conclusions of dubious quality.
While waiting for his trial in Nuremberg Hans Frank then completed his earlier task by constructing the "Frankenberger These" which is now often repeated but on so shaky grounds that it can be dismissed altogether, and this is done routinely by historians now. But interestingly, the revisionist historian Werner Maser claimed in his biography of Hitler 1967 to also dismiss the just mentioned thesis but that he had solved the mystery nonetheless:
Hitler was not descended from Jews. He was rather the product of a particularly dense inbreeding.
— Der Spiegel, 24.07.1967: "Dichte Inzucht", linked above
If you trust this magazine, at all:
Only once – it was already in the year 1919 – did Adolf Hitler slip out of a remark which shows that he considered valuable what the NS ideology later declared reprehensible: Inbreeding. At that time he explained how "the Jew in general preserved his race and its peculiarity more sharply than many of the peoples among whom he lived" – "by inbreeding thousands of years old, often carried out in the closest circles".
Inbreeding was indeed an idea that he could certainly relate to.
Wolfgang Zdral: "Die Hitlers. Die unbekannte Familie des Führers", Campus: Frankfurt, New York, 2005. (Journalist extending the slightly dubious work of Maser.)
Tiny commentary: it seems that quite some care has to be taken in balancing the description of internal discrepancies and logical pitfalls of racial theories versus using this information to just say that "Hitler was no Aryan himself". The latter is a captive of these theories and somewhat resembling an accusation towards nazis that 'they weren't racist enough'.