The term "rootless cosmopolitan" experienced something of a resurgence in popularity recently, so I think the uploader may have meant it in the modern sense. That being, a person who supports open borders, multiculturalism, does not value sovereignty or nationhood, and thinks people should feel no nationalism or patriotism and every country's people should be pretty much the same. Historically, Jews were among the few nations without a country, so they would supposedly move freely between different countries without feeling allegiance to any. Thus they have an affinity to such rootless cosmopolitan attitudes. That's the criticism, anyhow.
A person who moves to and fro as the fancy strikes him, can be seen negatively (bum, roving barbarian), neutrally (nomad) or positively (free spirit). Jews being historically considered a "wandering tribe", the artist of the image must have wanted to show them in a negative light. Hence imagery reminiscent of homeless riff-raff - the dagger across the belt (the Russian stereotype of a razboynik - an itinerant bandit), the scruffy appearance (he looks like a bomj - bum), the smug expression, all serve to make the figure appear a nasty, uncultured, comical nuisance. "The Jew is a wanderer! And let me remind you why it's bad to be a wanderer..."
However the image does not literally depict a bum, but uses it as a metaphor to criticize "rootless" people (who are not tied to one home). This is necessary because the typical "rootless cosmopolitan" is educated, well to do, well dressed and amicable - the outward opposite of a bum. Thus the authors wishes to remind us that appearances can be deceiving, and really the rootless cosmopolitan and the ordinary bum are the same when you think about it. Thus the scriptorial imagery: Just as the bum's antisocial deeds are enabled by his walking stick and dagger, the cosmopolitan is enabled by his (subversive) writing.
To drive the point home the man has stickers with names of various intellectuals who were considered the intellectual leaders (by the author) of cosmopolitan ideas. Many names are conspicuously Jewish, which I suspect to be no accident.
In sum the drawing makes the claim that most Jews are rootless cosmopolitans and vice versa, and criticizes both. Hence antisemitic in attacking Jews, as well as perpetuating many tropes of antisemitism.
Worth noting also is the low-brow Russian concept of an intellegent - intellectual. As used by petty criminals and uncultured, uneducated people this doesn't mean "interested in intellectual pursuits", but rather a weak man who dresses in a certain fashion. The fashion is roughly exotic brimmed hats, tweed and sweaters. Which is what this character would appear like at a glance. Compare to the American concept of a "nerd", with thick glasses, bowtie, pocket protector, white shit and nasal voice.