Okay, let's all take a step back here, because most of you seem to be missing the entire point of this strip.
It's not trying to say that Claire manipulating Clinton was right. It is simply Clinton realizing that that isn't what he's actually mad about. Period. End of story.
Yeah, Claire was still wrong to do so. But deep down, what really got under Clinton's skin is the rejection from Emily.
And that, friends, is all. Any additional meaning is supplied entirely by the mind of the reader.
That's the part that disappoints me about this entire storyline. Claire manipulating Clinton is what he (or, really, anyone in that situation, IMO) should be mad about, what the story so far made it look like he actually was mad about... and now it turns out that if Emily had said yes, Claire would never have been told not to manipulate people in the first place. I suppose, for the sake of Claire's character development, at least she did get called out on it, but now it's going to get walked back, at least some, because Clinton now feels that the problem wasn't the manipulation, but the fact that it didn't work.
This. The epiphany that Clinton seems to have had was, "If it had worked out, I wouldn't have been mad at Claire. Therefore, I shouldn't be mad at her, because she was just trying to help!" The epiphany I was hoping he'd have was, "If it had worked out, I wouldn't have been mad at Claire. I should be mad at her because she manipulated me, not because it went badly!"
Either way, Clinton should go home, sleep on it, and apologize to Claire for overreacting when he sees her tomorrow. However, there is a difference between "I got mad at you when I shouldn't" and "I overdid it, and I'm sorry, but I had a legitimate reason to be mad that we need to talk about."