I've come to the conclusion that this is a personality difference between "judging" and "perceiving" in the Myers Briggs sense. You seem to be solidly on the judging side of the spectrum while I'm pretty far on the perceiving side. Neither is "correct" which leads to arguments like this, judgers are annoyed by perceivers for their laziness and perceivers are annoyed by judgers for their pedentry and chauvinism.
Again neither is right, so the best thing to do is be aware of this difference and try to avoid the things that annoy people. Perceivers need to try to not make those grammatical errors and judgers need to not call them out for it.
On the political side yes we should be making the best possible arguments in the best language when trying to bring others to our side, I'd say my original comment wasn't trying to do that, just an offhand remark but either way. Along with that we should avoid calling out and judging people for the language they use, as long as it's coherent and not offensive, as that alienates people.