As much as I agree with Kyle's sentiment, I can 100% understand Jack's position here. In addition to wanting to remain eligible for movie and tv roles, he probably also doesn't want to get shot. Security for singers is probably more lax than security for ex-presidents, after all (at least most of the time). It's easy to imagine some troglodytic cultist piece of shit taking the band joking about killing their bloated lord and savior personally, and resolving to do something about it.