Yeah but also social media is just a medium. It's the people who create the culture, not the medium. Sure people adapt to other people but you still start somewhere.

Tumblr was popular with young people, women and minorities, and to this day it's overwhelmingly queer and female. Facebook was popular with young people but was quickly discovered by organisations and businesses as an easy way to be public facing, so over time it's become sort of more professional and inclusive of older people.

What kind of people used reddit? Before it got popular, it's culture was influenced by millennials, nerd culture and hobby forum culture. That's what's stayed. What kind of people use Lemmy? Well, that's the question isn't it?