Nothing confounds me more than the droves of "libertarian socialists" and "anarcho-communists" who insist on clinging to the world's least relevant ideologies. Speaking as someone who used to be an anarchist (before I became old enough to drink), I can identify at least part of the reason being a vehement anti-Soviet and Sinophobic worldview cultivated by decades of malicious propaganda.
But I don't think this critique gets to the core of their beliefs. The true operative factor is twofold. On the one hand, anticommunist "socialists" avoid the consequences that come from aligning oneself with actually-existing socialism. This boils down to the simple fact that no one, especially not the powerful, are actually threatened by western leftist "movements" which spend all of their time and resources owning the red fash tankies online. Functionally, radlibs and liberals are on the same team aside from some nominal points of disagreement. This is clear enough from the Ukraine news cycle and its predictable effects on the minds of these terminal losers.
But on the other hand, every single anarchist "revolution" ending in defeat and failure has advantages for those who wish to profess to the ideology. Within radlib mythology, the fundamental failures of anarchist movements can all be blamed on external sabotage. This, of course, is exactly what we have been shouting from the rooftops for decades upon decades. And yet this seemingly obvious point of weakness shields anarchists from having to prove that their ideas actually work. If you have no surviving socialist project, there's nothing to criticize.
Obviously, this is in actuality a serious problem for every anarchist. When all "anarchist" socialist states are fanciful stories of flawless communism sealed in the distant past, there is no scientific socialism and no historical progress along those lines. Apparently, this suits them just fine, though it does make them deeply unserious.
There are plenty of anarchists doing good on-the-ground work. And there are plenty of communists who are terminally online. As much as we make fun and get frustrated with anarchist analysis and their lack of historical knowledge, I don't think we can characterize either movement as a whole of spending the majority of their time dunking in comment sections. In my own experience with anarchists and other left tendencies there is not nearly as much infighting as you would be led to believe online. Plenty of people are doing the work and have their eye on the larger contradiction, which is opposing the bourgeois state.
The anticapitalist movement is still reemerging in the West after decades of McCarthyism and it's going to take time for people to become more learned about socialist history and ideology. Communism is getting more popular, albeit slowly. I personally think that the popularity of anarchism in the West is a phase that is temporary. Experience will lead people to Marxism.
The anarchist space performs an essential role for radicalization - it allows a way for someone to radicalize left without rejecting the narrative posed by the capitalist propaganda machine. This is how I was first radicalized. The capitalist propaganda is so pervasive that its easy to take many of its assumptions for granted. Even if you begin to reject the narrative, it's hard to avoid falling into the assumptions posed by it. Radicalizing leftward makes it easier to reject the capitalist narrative later, allowing radicalization to happen in phases.
Much of the infighting between anarchists and tankies is, in my view, created by the capitalist propaganda machine. By manufacturing conflict they make coordination between us more difficult, and also slow the radicalization process from anarchist to tankie.
Not to mention, so many of these public internet disagreements are likely involving bots.
CIA bots making bad-faith arguments to defame and fracture leftist movements, I suspect.