It's a large org and some chapters are like 10 libs that still think it's just a Jacobin reading group. Of course you're going to have outliers doing bullshit like that. DSA isn't PSL, for better or worse, it's an org that isn't ideologically rigorous, it's more of a meeting place for local activists and theory nerds.

Bernie was the only candidate that DSA was allowed to endorse and that was written into the national laws, so anyone doing this is breaking with DSA.