What, exactly, do people mean to signal when they preface a comment with "I know this isn't politically correct to say, but . . ."?
It is boasting? "Please acknowledge that I am brave, a rebel, a nonconformist, by being willing to say the following in defiance of social convention." Is it special pleading? "I recognize that the following may be considered rude, but please pretend that it is not because I have acknowledged it." Is it lampshading? "You can treat this as not-rude because I have pre-announced that it could be seen as rude." Is it strawmaning? "Nobody would actually be offended by what I'm about to say, but I'm going to pretend that some people will in order to paint them as ridiculous." Is it self-serious cross-climbing? "Contemplate, for a moment, how I will suffer for being willing to share great truths with you."
I ask because it seems so common, in public or private. Take the case of a 47-year-old Englishman who used LinkedIn to praise the looks of a 27-year-old Englishwoman, a complete stranger to him. “I appreciate that this is probably horrendously politically incorrect but that is a stunning picture," he said. The recipient shared the message and her rebuking response, leading to a flood of both criticism and support.
There are plenty of interesting issues embedded here. Is there some sort of social or moral convention that requires us to keep unsolicited messages private? (I lean towards no, in most cases.) If, for the sake of argument, an unsolicited message is rude, is it proportional or compassionate to share it to make a point about such messages? (I submit it depends upon the message, and the sender, and the recipient.) Are some women reasonably irritated by unsolicited messages about their appearance in professional settings and through professional channels? (I'll answer that obliquely with an observation that when I was a prosecutor, my female colleagues told me that after a trial, when they interviewed jurors, the jurors wouldn't necessarily comment on their trial performance, but at least one would almost inevitably comment on what they wore.)
But let's carve out just one issue: what's the guy signalling with "I appreciate that this is probably horrendously politically incorrect"? I don't see anything to admire about it. It smacks of "I sense on some rudimentary level that this will likely annoy you but I'm going to say it anyway, so deal with it." Or perhaps it means "modern norms of discourse annoy me and I shan't abide by them and I find it necessary to announce my defiance." Saying it strikes me as strengthening the argument that the communication is rude, or uncouth, or aggressive.
Norms about courtesy and rudeness change. Do you disagree with the changes? Are you trying to resist and push back against the changes? Fine. Speak, and let the chips fall where they may. But ask yourself: what are you trying to accomplish by such a preface in any particular communication?