I chuckled at your title -- thanks.
While the award is surprising and problematic, I can't help thinking that most of your putative people working for peace would either regard Obama's actions to date as meritorious (a position with which you evidently disagree) or welcome the opportunity that the award presents. It's not, as the newspapers are already reminding us, the first time that this award has been used to heighten a political leader's ability to lead a peace process or to elicit appropriate action from a politician. So, unless you have somebody particular in mind who is or ought to be offended, I tend to read your remark about a slap in the face as mock indignation.
I notice that the award is being welcomed by moderate figures in several nations, while Islamic Jihad has condemned it as political, pointing to the U.S.'s nuclear arsenal for support. (The person who made the latter remark would no doubt sympathize with your sentence about people giving their lives for peace; appeals to peace are a tricky thing, especially after George W. Bush.) This morning the militants' conservative counterparts in the US are already responding in kind, with a similar outraged moralism but a nominally opposite geo-political orientation.
The American liberal-left, if one can really speak of such a thing, might likely respond confusedly. It seems to me that many people's initial reception of Obama as president was over-emotional (though not difficult to understand, on the heels of the previous administration) and gave rise to inevitable disillusionments, often founded on the same kind of moralism and disregard for politics we see in the American right when it's not trumpeting an execrable political realism.
So it could be difficult to situate oneself in relation to this announcement, and perhaps there is a problem in feeling compelled to do so -- in treating politics as demanding the same kind of ready judgments that we, unfortunately, are all the time urged to make about art. I don't mean to say that we should suspend judgment, since politics is above all about practice. But these particular kinds of judgment strike me as ideological in the classical sense, and I would suggest that they can distort people's understanding just as the initial jubilation on January 20 did.