Why would they? They're well pass puberty. Getting off isn't the only reason to look at such images.
They're not the so-called Crusaders, if they can find the images to post here, they don't need to come here to look at them, partially obscured with captions, no less. And long videos, instead of a R-Rated pic or short gif.
The 'Crusaders' were a group of middle schoolers who would raid these streams. Problem is, they eventually would hit puberty, one by one. There was a lot of infighting, as quite a few of them would post links to each other on other memes on other streams, as in, "Look at this one, it's icky, grrrrr grrrrr."
They were even told by site mods that if they have a problem with potential porn to report them, not post the link for others to see.
These kids were complaining about TOS violations, but they were violating the TOS by posting the links everywhere, sharing them. Which is exactly what they were doing by intent.
So they imploded, streams would collapse, and then they would start anew with yet another stream, and repeat.
Evidently on account of me their parents, their online access was restricted, so yes, they came looking for such material and shared them with each other under the guise of fighting against them. It was pretty funny seeing them attack each other when it became obvious that they were just trading links, not flagging them.
Those who participate on these streams do so for the same reason other people looking at other types of images on other streams do so. They like it.
You were talking about this on some other meme, I was going to post something there, but I can't find it now.