It is currently still unclear to which extent and from what angle "any ridicule" might have come. Of course there was some ridicule towards those uniformed men, and of course that ridicule mainly came from political opponents.
Uniforms of all kinds were still in much respect and fashion in Germany. Be it old Kaisers Rock (Prussian uniform, including equivalents from other states), police, firefighters, then later communist fighter brigades or mainly Social-Democrat fighting brigades.
Unless that angle is better focused and explained, this answer will be restricted to address a common misconception about 'the uniform' as apparently informing the nature of the question — and most certainly a lot of comments.
The SA was called at a time Braunhemden (brown shirts).
That is significant, as the history of the organisation has to be looked at in the different phases.
First phase: 'a Jew' Emile Maurice creates the sports division of the party, which attracts ruffians, mostly from the Kaiser's military and later Freikorps. They wear their old uniforms, pretty much rag-tag style. When they try to appear 'uniform' in public the colour grey dominates for windbreakers and the only real identification signifier is the armband. The name Sturmabteilung was only chosen in 1921. And up to that point, no SA man wore brown shirts for party affiliation (ie: in private they might still have liked to don one).
An independent Freikorps Roßbach comes into view. He is a right-wing extremist, has his own Freikorps, and two coincidences on his side. He organises a holiday bike ride for his comrades to East Prussia in 1921, now under a more inoccuous name ("Verein für Wanderfahrten"). To appear in uniform style, he choses for his outfit a small surplus under his control from decommissioned colonial stocks. Out of those the intended but never delivered newly designed light beige-brown shirts for the East-Africa Schutztruppe under Paul Emil von Lettow-Vorbeck fitted his bill. These were and are nicknamed Lettowhemden ('Lettow's shirts') after the officer whose troops were the intended receivers of the uniforms including the shirts. Those were never made again in that exact style, stocks ran out fast but the impression of uniform earth-like colours for earth and ground (Blut & Boden) loving right-wingers catches on. Mainly since grey stood for the old field army, red the communists and firm black by then in use by Italian fascists.
The name Lettowhemd is still retained, informally, and giving rise to much of the misconceptions on display here. But the colour, cut, material etc differ substantially from the later 'Hitlerhemd' (as so called by Roßbach). The later and latter is much darker brown, less like a fit for an African bush soldier, more like one for an Alpine huntsman.
During the prohibition of the NSDAP phase, such outfits were not opportune in general, and until then the spread from Bavaria into North Germany wasn't as big as later.
The basic 'uniform' style for the SA was then sought to be standardised in 1926 through the party, while wearing such a brown shirt was already made compulsory since 1925. They ordered large contingents of the same basic style for the masses, not least for brand recognition and corporate identity reasons but also to make that more affordable for the lower strata of society filling their ranks.
That went in parallel with really well-off members getting their shirts tailor-made while right up into the 1930s really poor members still making their own shirts for simple price reasons. While buying in bulk the centralised Sportversand made quite an income from its margins. This variation in styles is seen in trousers as well, and it becomes evident when looking at authentic pictures from that time.
This picture showing the important members Heines and Röhm in 1933 shows some variations:
It shows Heines, the SA hothead who in his own heyday introduced a basic brown shirt, first as a 'real uniform' into the youth organisation Schilljugend, after Roßbach's idea and following partly the style of the previous colonial gear.
So, for well into the 1930s, it is hardly 'the uniform' of the SA to speak of. Official regulations standardising every last detail of that later uniforms that we might associate readily with such advertising masterminds like the nazis can not be used as a template to look for validation during the earlier phases. The most basic derision towards the SA's outward appearance was more to the lack of uniform (and the truncheon-swinging loudmouth behaviour of course) because they were right-wing but often poor, an unnatural combination.
— Freikorps Roßbach, 1919-1923
— Sturmabteilung (SA), 1921-1923/1925-1945
— For the Roßbach/Lettowhemd angle: not WP: SA, but
— Gerhard Rossbach: "Mein Weg durch die Zeit. Erinnerungen und Bekenntnisse", 1950. (Chapter: "Meine Beziehung zu den Braunhemden" describing the original Africa-destined shirt he bought up in detail, quoted in a short but easier to access manner here.)
— Freiherr von Eelking: "Die Uniformen der Braunhemden", Zentralverlag der NSDAP Franz Eher Nachf: München, 1934. (archive.org; bad barely readble scan but correctly shows some developments roughly correct for the timeline in pictures, of course much oversimplified as well and never mentioning then already disgraced persons…)
— Daniel Siemens: "Sturmabteilung. Die Geschichte der SA", Siedler: Berlin, 2019.
Since the fashion topic 'uniform' was of course generally rejected wholesale by pacifist or 'strictly civilian' circles after the Great War, it retained much appeal in German everyday life. In fact, I'd argue that when the SA finally gained some more ground during the later 1920s, while they adopted more stringent uniform-like appearances, they were more of a trendsetter in that regard for the opposing sides, who in part also wanted to appear 'en bloc' on the streets (and according to the SA source Eelking did so before the SA arrived at the brown basics).