Is there actual evidence that such content causes harm, or is this the usual “think of the children” FUD ?

I know it’s a sample size of one, but being exposed to violent & explicit content as a kid doesn’t seem to have ruined my life in any way.

Finally, any kind of “filter” would be ineffective; as kids will still find ways of exchanging such content offline. If anything, making the content forbidden would make it seem more appealing.