It's not an invasion of privacy at all. He signed up for an email account with a company that in the terms tells you they read said email for targeted ads. There's no illusion of privacy there. Now if he was paying for that email account with his ISP then they rummage through it that's different.bu bu bu only computers scan your emails!
While this perv is disgusting and should be hung by his testicles in the middle of the desert at high noon, the invasion of privacy is shocking.