I can't accept the backdoors either. Clipper was a bad idea then and any iterations of it in the present are just as bad. Clearly that is not the most effective way to attack the child porn problem, Microsoft, for all its faults has done more to combat this than lots of other parties combined, including most nation states. Properly funding various services including the LE branches responsible for dealing with these crimes would be the way to go and that does not require any backdoors at all. The mountains of proof that are usually unearthed are strong enough for conviction, the bigger challenge is to roll up the networks but there are ways to combat that that do not require access to the payload.