I agree, it's freaking annoying. I tend to just avoid scrolling the new memes in "fun" since the content is so dang immature and yeah, all Fortnite and Minecraft. (Page 1 of "Hot" in the fun stream is at least always good for a laugh)
But, hey, they haven't had life experience yet... what else are they gonna meme about? They're not going to become top-notch political debaters overnight or have a sense of awareness of the irony and situational comedy that appeals to adults.
I have a whole new stream now dedicated to sex (shameless plug: imgflip.com/m/SexStream
), where I necessarily post and feature mature content. There are plenty of adults on this site, too, and I don't think the fact that there are kids here is a strong reason to self-censor
If these kids really wanna see boobs online... they're gonna be able to one way or another.