As long as there is no harassment/outsiders using it like 4/soc/ (like how https://dic.pixiv.net/en/a/PTT#h3_2 does too), I think noone really cares if the user is actually a male or not. You can read in the rules that it's for girlish topics, a male is less likely to play otome games or listen to Barbie but they could of course post if a relevant topic exists.