Rick had learned to distrust strangers, and the backpack guy was a stranger. Maybe he should have helped him. I doubt he was dangerous, but after what Rick had gone through, I can't fault him too much for his mistrust. I can't absolve him completely, but I understand why he did it. Father Gabriel on the other hand locked out people he knew and cared about. Left them to die because he is a coward. I think it's inherently worse to do something that may harm people you supposedly care dearly about than it is to do something that may harm a stranger.Of course, if the backpack guy had lightened his weight load, he could have survived, and if the people at the church realized sooner they weren't getting in, they could have survived. Still, I think the fact that Gabriel did this to people he knew and cared about makes what he did worse.

 

Pretty much. Packback guy was an unknown, and he came along at a time when Rick's group was already spread thin dealing with bad guys and dangers to his family. Also, there was no immediate threat to backpack guy at the time. He had been travelling on his own for awhile it seemed, and was loaded with gear. The folks outside the church were people Gabriel knew, and he didn't let them in even when an immediate threat came along.

 

basically, this. gabriel left people that he knew to be eaten alive, in a position where he was surely able to hear it happen..he must be riddled with guilt

 

Rick was in the middle of a war situation with the Guvnor, he couldn't risk an unknown quantity with his group. There just weren't the resources to quarantine him and then let him into the main part of the prison, not in the middle of a war.

Gabriel knew the people. He killed far more than one backpack guy. They trusted him and he betrayed them, and he's a man of god!!!!!

 

Rick is also paying attention to Carl and respecting his decisions more than he was back then and Carl gave Rick a head nod when they heard Gabriel screaming. As we have seen numerous times, Carl always wants to save people from walkers.