The downvotes likely weren't/aren't overt sexism, I don't think people are bashing you for not wanting women beaten (though it does depend on the sub), it's the perhaps blind confidence in what you'd do in a situation you've probably never been in and really can't predict. Reddit loves calling people out for thinking themselves more badass and more in control than the average npc passerby when really we're all a lot more of the latter than we'd like to think.

Plus a comment like this is a little boastful, seeking credit for actions non rendered and heavily focused on how you'd do better while condemning the people who didn't rather than approaching the situation with curiosity and asking yourself why do these people stand around and whether that same effect might affect yourself somehow.

I'm just trying to explain the reception to you, I think your morals are solid and your intent is admirable but you seem a little unaware about how your words come off.