Where to even begin on this one!? I think in general, a line needs to be drawn where sensitivity is overshadowed by the invention of sensitivity. It could come across as disingenuous simply because it is the RIGHT thing to say. It also discourages people from thinking differently. There are some things that are just wrong to say because they are mean and disrespectful towards another person. The idea of “political correctness” was made for people who have no idea where the boundary between discriminatory and constructive lies. In some ways, this idea takes away our freedom of speech about certain politically important topics and can encourage the opposite effect on the opposing people group – sort of like reverse racism. Slandering another people group is always wrong, but sharing a mutual joke between friends isn’t wrong, and neither is engaging in an intellectually minded debate.
The long and the short of it is, use your brain! If you wouldn’t want it said to you, then don’t say it! If your argument or discussion relies on ad hominem then you need to rethink your position. I don’t see why people can’t call it as it is. Say what you see, just use common courtesy, and your brain!