I don't understand, why do Christians not like Masturbation or porn

[robvalue]

Of course they do. It's part of the "You just want to sin" thing; which translates into, "I'd be doing that if I didn't think I was being judged by an invisible being". Otherwise they'd say, "Why would anyone want to do that?"

Out of each 10 people who claim to have never masturbated, I'd guess maybe 1 of them may be telling the truth.

Objections to porn can at least have some grounding in reality, so I can accept that.