Why do women (25-55f) act like I’m doing something wrong by having guy friends?

Most of my friends are from martial arts class, and I’m the only woman in my class so naturally this is a group of dudes. They treat me as a peer and have a great group.

I hosted a party not long ago. Only one woman came. She seemed extremely off put by the gender skew and told me I need more lady friends. My coworkers, who are women, acted disgusted when they found out that my friend group is a bunch of dudes and told me that guys should only hang out with women if they are visiting as a couple (ex- bringing their gf//wife). They were perplexed as to why I would want to be around a group of men.

My husband knows the guys and is completely comfortable with me hanging out with them.