I think his quote was based on all the crap Amy has had to go through with Sheldon. Obviously it wasn't based on anything in regards to the actual show but his feeling how Amy puts up with everything that he does wrong. Someone earlier asked why did Penny still marry Leonard after what happened with Mandy. JMO but I think Penny realized all the things she had done wrong in her relationship with Leonard. Without Leonard's effort there would be no Lenny. Thus she forgave him.I can't say the same in regards to Penny's effort. The same holds true with Shamy. If it wasn't for Amy's effort there would be no Shamy. Again I can't say the same in regards for Sheldon's effort. In regards to this episode Sheldon did some things wrong intended or unintended. What does Amy know? She knows Sheldon was hanging with Ramona. Leonard was trying to get warn Amy what was going on. Then all of a sudden he shows up at her door at Princeton. What does she think now? If Sheldon tells her about the kiss what will she think? just me but I don't think Sheldon deserves the benefit of the doubt as Leonard did. And that why I think the original poster meant with that post. If she says yes there is no reprocussions to what happened.
Again JMO that's true if she says no. If she says yes there is no lasting effect. There already living together. No different than when the gang found that Lenny was engaged. In that case they were more excited about Raj and Emily.