Anyone else not blame Tweener for ratting?

Back in season 1, Michael was using absolutely everyone in Fox River besides Lincoln - remember, it was originally just supposed to be him, Lincoln, Abruzzi and Sucre who escaped and he probably initially had plans for Abruzzi (and Sucre before he got to be friends with him) to be recaptured fairly quickly afterwards; every extra person that got added to the plan was a potential liability. And while I don't necessarily blame Tweener for snitching, I do think that he brought quite a bit of trouble on himself. He antagonised a lot of people when he first arrived by trying to act tougher than he clearly was, and (to put it bluntly) being a white boy trying to attach himself to the POCs. And Michael actually went out of his way to try and protect Tweener a few times, particularly from T-Bag. Bellick was more responsible for what happened to Tweener than Michael was: he's the one who backed Tweener into a corner and forced him to become a spy for him in the first place and then put him with Avocado when he didn't come through and sided with Michael.

As for why Michael was so cold to Tweener after he found out, like I said, every extra person in on the escape was already a potential liability. But at least the rest of them, for all their various issues with each other, ultimately cared too much about getting out themselves to tell anyone else or to truly risk endangering the plan (except for T-Bag and Michael tried to cut him loose several times too). Michael really only cared about getting Lincoln out of Fox River and Tweener had significantly jeopardised that. To be honest, I don't think we're ever meant to think that Tweener snitching was unforgivable, it's more tragic than anything. He was caught between a rock and a hard place and tried to pick the best of a group of bad options - at the same time, we know Michael's got a very good reason for being angry at him. Tweener's entire storyline on the show is essentially one tragedy after another.