Okay, the thing with Oz is that his ... views on people are a little skewered. He's very much a forgiving person, even if that same person will come back and hurt him! Hell, when Jizabel was in camp, he killed Oz and Oz still forgave him! It has less to do with the person and more to do with ...Oz's own self-worth. Oz doesn't see anything done to him as a wrong so for him, he's not really forgiving than he is saying, "oh, what you did to me doesn't matter 'cause I don't really matter!"

Moving aside, he gets that being controlled sucks and Tyki regrets it, so Oz tried to help! It was logical of him to do so! That being said, Oz still knows that Tyki is... well, he doesn't trust him yet, but he's more willing to listen to what he has to say than before.