It’s not denying anything. It’s clearly showing that what you say on the internet isn’t based on your true beliefs.

It happens all the time in actual court cases. Someone say “i hated John” and that’s used to show motive so the defense beings a witness who said the defendant drove John to church every Sunday.

It's just that it's a weak defense because the prosecution will make the argument that you committed your crime in one of those periods where you held malicious beliefs, in an emotional state.

They only need to demonstrate that you had motive sometimes, not all the time.