OK... so this has to be either cultural differences, or me being an idiot, because I honestly read the situation completely differently than most people seem to.
First of all, a mandatory disclaimer: no, I don't think Claire did the right thing. I think what she did was both stupid and wrong.
That being said... I think it's normal that close friends and family sometimes meddle in their close ones' lives. It's not desirable, but it's within normal parametres for such a relationship. Honesty and communication is the way to go, but I see what Claire did as thoughtless and her being a bit of a manipulative jerk. Not much more.
Clinton's reaction? I don't actually blame him for flying off the handle, because he was upset and such. He lashed out at the nearest person, and I don't think most people would do otherwise. But saying that Claire was "a real asshole" and that she should "fuck off" made me go "wow. Seriously?". Again, it's understandable, but I feel it's not even remotely justified.
Claire's attitude was patronizing, but I don't think a family member or a friend thinking they know better and helping someone against their will goes beyond, again, being kind of a jerk. And, again, maybe it's a cultural thing, I see people meddling in their family's personal affairs as a semi-acceptable thing in my neck of the woods. It pisses me off in most cases, but apparently it does not piss me off nearly as much as most people in this forum. Or Clinton, for that matter.
I've never done anything resembling Claire's setting Clinton up, mostly because I'm clueless and have the social graces of Harpoon Lady (OK, maybe not THAT bad). I guess I'd usually be the Clinton in such situations, not the Claire. But if I did something clumsy and thoughtless and put someone in a kinda-sorta-bad-but-not-really situation, and they told me to fuck off, I'd probably, well, happily oblige and fuck off. Which is to say, give up on any interaction with the person at least until they cooled off.
It's entirely possible that I'm completely misreading the situation, but I am genuinely surprised by the amount of condemnation Claire is receiving, here. My reaction and level of pissed-off-ness is about on the level of Marten's comment from a few strips back, I guess.