It's good you find co ed groups comfortable but the reason most women look for women-only groups, it's because men start sexually harassing women or mansplaining and putting women down. I tried to join coed groups for many hobbies and even in an atheist group where you'd think there would be less of the christian "gender roles", I still felt women were disrespected and they made fun of feminism.

Literally all atheist pages I follow on Facebook have some sort of misogyny there. That's why I looked for women only atheist pages. I feel the same with hobbies. It's either men acting shocked a woman likes the hobby and being condescending/gate-keeping and testing your knowledge or they are overly friendly at first and then starts the flirting which escalates to straight out sexual harassment. There's also the fun when men push women of the group to sort of fight/compete against each other which is very annoying and again, it's like male dominated environments or coed groups can't let go of gender roles. I do think there's some hobbies out there that cater to female gender stereotypes which is why it could be uncomfortable to be in a women-only group but I take that over being DM'd constantly by men harassing you or having to listen to men being hostile just because you're a woman.

Frankly, I'm surprised there's women out there that are comfortable in coed or mostly men groups cause I've found them very uncomfortable.

I can only wish more co ed groups would be more welcoming and less hostile to women.