I don't think that pic is at all funny. A person that finds humor in that is sick and twisted. But what annoys the HELL out of me is if I say that picture is offensive I'm being the uptight asshole (at least according to some people here).
I think your judgment has some validity if you think they're laughing at the pain of the poor girl in the middle. I don't find that part of it funny at all.
What makes me laugh (in a very dry way) is that the images are entirely discordant and do NOT belong together whatsoever. They're entirely inappropriate.
I think this is a style of humor you overlook. I guess it is more of an impersonal/intellectualized style.
When I look at that picture, I can laugh at it AND be offended by it all at once.
But even then, context still matters. Because Carebear linked to it (and warned people up front), his intentions seemed to be not to offend. So I look at it in that vein.
If someone else who simply likes to shock people and has no seeming regard for feelings posted it as part of their onslaught, I would probably read it as offensive.
And it were brought up purposefully to show a vietnamese orphan or someone who survived a bombing of their hometown as a child, it would be sadistic.
Humor's a slippery thing, isn't it?
I think if anyone would judge you as humorless/uptight (as per your quote above), it would not be based on you perceiving the offensive qualities of this particular cartoon but for failing to recognize (or not caring to recognize) that there other ways to look at it (more impersonal) that are not directed hatefully towards others.
It's like laughing at the absurdity of a tragedy in life, even if you really don't find it funny on the emotional level. Absurdity, incongruity, dissonance all can evoke a normal "humor" reaction in some sorts of people who are still mature and sensitive. I don't know -- have you ever had that sort of reaction to something just god-awful you see or hear on the news... because it's so crazy, so absurd, so ridiculous that it never should have happened?