It's amazing how many people seem to equate being "politically correct" to being "polite" or even just not being a raging asshole to other people. So, if we are talking about political correctness, let's define our terms first, shall we?
Being "politically correct" means not saying derogatory things about traditionally persecuted groups, because doing so is a type of persecution. That's why there's the word "political" in there. Because if you are dealing with an individual and you say derogatory things about a group this individual belongs to and/or indicate that the individual in question is not even an individual to you, but merely a representative of that group, and that you despise that group, what you are doing is a political act. You might be being an asshole too, but you are doing something distinctly different from (for example) telling someone they are ugly. What you are doing is contributing to the persecution of a group.
To that end, not being politically correct makes you an even bigger asshole. But sure, if you want to be one, that's your choice. That's the other thing about being "politically correct" is, it's not legally enforced. I.E. you can't go to jail for being politically incorrect. You might want to brace yourself for social consequences, however, i.e. being criticized and being called an asshole. That's freedom of speech at work.
As for "everybody needing to be offended from time to time"... do you honestly believe that people who belong to persecuted minorities somehow lack reasons/opportunities to be offended in their lives? And even if you did believe such a preposterous thing, how does it make it your job to offend them, or give them a dose of "reality"? In addition, even if you believe that and also believe it's your job to offend people, why do you think it's important for you to offend them in specifically the way that makes the offense politically incorrect, i.e. by invoking and participating in the persecution of the group(s) this person belongs to? Can you not just be offensive in any of a million other ways? It really doesn't take that much effort or imagination...
It seems to me that people who love to bash "political correctness" are people who are somewhat deficient in social graces and can't seem to avoid offending people whether they meant to or not, but don't want to face social consequences (i.e. being criticized and disliked) for this. That's why they like to conflate "political correctness" to politeness or not offending people. That's a neat little straw man, but it doesn't actually get you off the hook for offensive behavior. Granted, it's almost impossible to go through life without ever offending somebody, but the correct response to "accidentally" giving offense is not by doubling down on being an inconsiderate asshole. Also, I realize that public opinion is not even remotely infallible, but maybe if something you are doing is consistently offensive to a lot of people, it's worth re-considering your position every once in a while (even if you keep coming to the same conclusion), just, you know, to see if you might think of new reasons why everybody is on your case about it.