I think it's hard to pin down real demographics in a visually anonymous medium.
Some games, people are all up in everyone else's RL business and know these things -- most common on smaller games with a small number of people who know each other fairly well or interact often.
Some people would rather not share this information, period.
Some folks don't engage OOC at all if they can help it, here, on the game, on discords, etc.
And MSB represents a small number of people in the broader MU hobby, even if it's 'just MUSH/MUX/Evennia/Ares games' and not RPIs and MUDs.
Plenty of people on various games I've been on assume I'm male -- mostly the adult games, and the reason cited is typically, 'but women are all subs and enjoy humiliation!' Uhm, no, darlin', no. (If I heard about how I was definitely a dude playing women one more time because I didn't giggle or smile enough, I might have broken a knuckle on the monitor.)
I've guessed at unknowns and been wrong plenty. People have done it to me. So I'm really reluctant to make assumptions here about the over all makeup of the hobby.
I think -- as Generic White Girl #367, so apply however many grains of salt you feel appropriate -- we're better off, if we want to improve things, assuming people of all races/religions/genders/etc. are present in the hobby, and we should consider their comfort levels as the default.
Being a healthy, inclusive space is the best invitation and advertisement.