Re: Two things

It doesn't need to be all, or even most. (Though I do think it is a majority, however not a large majority: more like 60% than like 90%)

Antis say that no child ever thinks about sexuality (unless they have previously been sexually abused); that sexual thoughts are simply nonexistent in them. Because of this, a complete ban on any exposure of sex to them or any sexual action with them can be justified as "Developmentally Incorrect".

The fact that at least some children are interested in sex, makes these blanket prohibitions not defensible on that basis.

Of course, it is not that technology is "sexualizing" children (as some would say, in a last ditch attempt to save the original argument). Technology is simply there helping them express things that they couldn't express before, or found much harder to. And it is also (unfortunately) getting at least some of them caught much more easily than in less technological times.

But I certainly don't think that all the kids are sexting. Only that every kid that does it is one more piece of evidence against the "essentialist innocence" position of antis.