I know they're out there, I know there's way more sports-following leftists than sportsball folk but holy shit, it's impossible to discuss sports on reddit in r/soccer or r/nba lest you get severe chud/liberal brain worms.
IRL pickup games are an easy way to make friends with non chuds but I are there any sports spaces on the internet that at least more left leaning?
This doesn't really answer your question, but I like saying it so I'm gonna repeat it here too.
Sports media conditions viewers to identify with the owners rather than the players. (especially fantasy sports). So lots of the 'sports' places online are full of people talking about what they'd do if they owned a team rather than people looking to form a pickup league.
To second this, most people know that they would suck if they played and/or also literally dont have time to play. Even most rec leagues require too much dedication and consistency and are only available to weekly 9-5 ers, which isn't most of the country at this point.