Gene Roddenberry's proclivities aside, Star Trek is still a capitalist enterprise (pun intended, come at me petaQs) written and produced by capitalists to entertain a capitalist society. To that end, I would see most of the series' criticisms are from the perspective of liberal progressive, even neoliberal, but not necessarily communist (in the sense of anti-capitalist), ideology. More often than not, Trek's "communism" is undermined and turned into window dressing, because of course it has to play to the God fearing Commie hating mainstream.
Earth didn't reach post scarcity by seizing the means of production through class warfare, but scientific and technological advancement and culture shock from first contact with the Vulcans. The Bell Riots you're talking about in the time travel episodes are probably the strongest explicitly socialist part of recent canon, but within that canon they still didn't result in an anti-capitalist revolution since the themes the writers wanted to touch on were homelessness and sociopolitics from the 1960s and 1970s (Attica, Kent State, etc.) The Federation doesn't require its member worlds to be communist nor does it foment revolution in potential member worlds. As portrayed, most Federation worlds appear capitalist in some form.
People have jobs with clear non-collectivist hierarchies (see Sisko's restaurant.) We're just supposed to accept that this is entirely voluntarist, but the whole issue of how labor in this post-scarcity society actually works is swept under the rug because no one writing the show actually cares. The pacifist Federation flagship whose only purpose is exploration and diplomacy carries enough firepower to glass a planet, and it uses that firepower often. "God" is an alien and a jackass but also somehow working in humanity's benefit, and as often as Trek espouses atheism, it does a wink and a nod to theism. Even the relatively low bar of gender and sexual equality was often undermined by producer Rick Berman's homophobia.
The Ferengi (ignoring the first few appearances) are explicit parodies of American capitalism, but they are also portrayed sympathetically and heroically, and often used to criticize the Federation's own ideals and human nature (see Quark and Garak's famous "root beer" scene in DS9[0].) This is obviously a criticism of American cultural propaganda but is also slyly pro-American imperialism, since of course the (deeply America-coded) Federation will sweep in, guns blazing, kill the (asexual and trans-coded) evildoers and save everyone.
So I have to disagree. If the goal was communist propaganda, they could have done a lot better.
[0]https://youtu.be/3bskhLaJYd8