CSAM is more accurate as H2O is more accurate instead of water or NaCl is for salt. Doesn't mean that you have to use it, and when the word pornography is used after the word child, everyone who is sane should know that it's wrong

Are there really people dumb enough who think CP implies that the children consented to that?

I think CP is a simpler and clearer term than CSAM.

My advice is to know when to cut losses. If they don't mean harm then just don't reply to them, if they do mean harm then report them.