It basically has to skew older, probably 25 to 30+ The vast majority of those younger are going to be on tiktok, sc, insta, or something like discord. Lemmy will be considered more "left" overall than even reddit was. There will be of course bad instances, but i think pressure to defederate from them overall will be strong, especially when the "free speech" instances start having difficult legal questions thrown at them when their users inevitably start saying the quiet part out loud.

Tumblr i the only other real leftist space I think. You could maybe put baseline social media is somewhat leftist, tik tok, instagram, snapchat, most of those have a leftist lean, primarily because they trend younger. Your general use social media is going to have a left/right lean based on age demographics. That's just the lean those general social medias are going to have.