OP didn't ask about "feminism" by the dictionary definition but specifically about disagreeing with modern feminism. I think if you actually truly don't want to fight gender discrimination because "muh biotruths, women belong in traditionally feminine fields only" etc that's obviously shitty and contradictory. BUT I'd say you can disagree with a lot of the mainstream modern feminist ideas propagated by the big-name talking-heads and still be a socialist.
A lot of trendy modern social justice thought gives only a cursory glance to the fundamental issues with capitalism and the general unfairness surrounding wage disparity. I've seen "progressives" exhibit some downright conservative "bootstraps" ideas about poverty as long as it concerns "privileged" groups.
I've personally not used it for a long time but it's literally just an insult. Calling someone an idiot has no rhetorical value either.
So yeah in the way OP used it, it's definitely too vague.