Paul thought Gotti was a heroin dealing punk, the tapes would have proved that. Once Neil passed, Gotti would have been killed or shelved.

He had to act first, not much to lose at that point.

Also, didn't they ask James "Jimmy Brown" Failla and Joe Gallo before the hit and they was like "eeh" don't really care ?

"In onore della Famiglia la Famiglia e' aperta"