I don't think we can compare the two situations. You're not him, you're not motivated by the same things that cause him to act. And you were already showing signs that you disagreed, that you thought muggleborns should be treated better and so on.

Yes, you found out but you're a different person. And I'm not saying he'd betray us. I don't think he would do. But I also don't think that just plunging him into the lock is the right way for him to find out.