Naturally they'd align with a competitor system, most likely the most prominent one
Tbh, though, from my brief reading of the subreddit in question, I don't think it is particularly politically charged or cohesive. Sounds more like a lot of people with aligned complaints gathering to, well, complain
Curious to see whether this will extrapolate from the US to other places, too
While the growth of the subreddit has somewhat polluted the term on the Internet, "antiwork" referred for years before the subreddit to a particular line of socialist thought that often rejects labor outright.
Texts like The Right to be Lazy (1883), Labor and Monopoly Capital (1974), and Willing Slaves of Capital (2014) are all decidedly Marxist and indicate that this line of thinking has a pretty long lineage in socialist circles.