Just played through this scene yesterday, it's frankly disgusting. I'm not squeamish, I've worked in war zones, but this was completely uncalled for.
It's not even remotely funny, so you could hardly call it dark humor as the "joke" at the end is entirely on the victim. The victim for all anyone knows is innocent, there is nothing at all to suggest he is anything other than a guy unlucky enough to meet the wrong person once and provide a description. And the information from the torture checks out, so you could hardly call it a skewering of torture as a way to gain information.
Then to top it all off, the entire mission is scored on how nastily you torture the victim.
There are some instances where the game gets the tone right and is funny, but I found a lot of it borderline and unfunny. At times it is just plain nasty (take Floyd's treatment by Trevor for example). There are moments I feel really insulted as if Rockstar thinks we're all moronic teenagers like Michael's son to find this shit funny, despite the mature rating.
This crap really is giving games a bad name. I'm all for realism, freedom of speech and violence in context, but this was pointless. Rockstar won't care as I didn't buy many of their games previously either, but I'm not supporting this silly shocking for publicity's sake anymore.