i ultimately don't like people telling me what words i'm allowed to use. i'll decide how i want to speak, not you, and you can go fuck yourself if you don't like it. i have no remote concerns about your feelings; i'm strictly concerned with my rights to free expression, and if you want to restrict my right to expression in any way, you are my enemy and must be smitten and destroyed.
until relatively recently, i would generally avoid calling somebody a retard because it was unnecessarily rude and tended to reduce the quality of the discourse. it was just unnecessary to resort to specious ad hominems; i could insult your position, instead of insulting you directly. it was more effective to merely imply you were a retard, and not helpful to actually point it out. it made me sound brash and uncouth. i have a better vocabulary than that. really. however, when these retards on the fake left (they're actually the far right. the left doesn't restrict speech, only the far right restricts speech) started trying to tell me i couldn't use the word, i felt it necessary to start using it just to assert the fact that i can and i won't be told otherwise.
what this is about is rebelling against an authoritarian culture trying to tell people what they can and can't say and how they can and can't think. people of all ages and all political alignments don't like that and are likely to spit in the faces of people trying to control them through policing their language, and kick them down the stairs and tell them to fuck off.
it is actually one of the basic principles of ideological liberalism to reject authoritarian control structures trying to police language or create categories of thought crimes. i consider my insistence on the right to call you a retard to be a left-wing position and those institutions trying to shut me down to be on the far right.
it does not align me with any of these groups at all, and i'd like to see more socialists be more vocal about this. the politics of restricting free expression is a losing political position, and these guys (they are 95% men) have co-opted a foundational principle of the left that the left needs to aggressively and assertively take back from them. this is our policy and you can't have it; fuck off.