[He winces; yeah, he kind of walked into that one.]

He can just argue that as being a retaliation after getting attacked. It seems like it's an obvious villain move, sure, but if you look at the grand scheme of things, it was kinda brilliant: The Avengers made a big deal about him being the bad guy, wanting a truce and all that, and then he goes and publicly reveals that they attacked him first. It actually earned him some sympathy. Not to mention that by not killing Hawkeye, he gave the impression of being merciful.

[How's that for subtleties?]