1st time watch observations: The team celebrating Zack’s return in season 4 E5

Like most people I find myself a bit fond of the character but it doesn’t make sense to me

Ok I get that he was “seduced” to a dark depraved place due to weak personality traits being exploited and they all probably felt guilty about not seeing the signs sooner, but didn’t he make conscious and willful choices to help that monster? Building the teeth, hiding & manipulating evidence, planting the explosive, etc?

I can understand the individual visits with him at the institution but what’s with the welcome back group celebration meal with him as though he were a kidnap victim and just rescued from captivity? Hadn’t he escaped from the institution he’d been sentenced to to get there? AND at this point everyone is under the belief that he is the one that killed that Porter/Lobbyist guy (except Sweets). The whole thing just felt really off

Or was this an attempt by the writers to make up for the abysmally stupid cannibal apprentice storyline?