I wouldn't say it's so much that the inaccuracies don't matter. It's just that a good number of the inaccuracies are closer to people having two different, clashing conventions about how to use the language. In a lot of cases both conventions are equally acceptable and so those who might say "you can't say x, it's y" might actually turn out to be wrong. Often there is a choice. Sometimes it's even wrong to "correct" certain mistakes that were actually just made-up rules that have no origin beyond some poncy 19th-century grammarian thinking that English should be rigid. At other times it might be the convention now to say one thing rather than the other, but say 50 years ago it worked a different way and in another 50 years' time it will work in a different way again.
The result is that while I'd encourage accurate language I'd also suggest that people show more flexibility about what this actually means. The primary criterion for good English is that the listener and/ or reader should understand what's being said. The rest is rather up to the speaker; and, whilst I do still cringe whenever I read "it's hat", or "outside of the room", or "ten items or less", or some such, it's still better to overlook it in favour of not getting distracted by minutiae, especially when in each of these cases I think it's both clear what's meant and the "correct" forms in at least two of these cases are actually up for debate. The risk is something called "hypercorrection" which is often what's going on when many people try to "correct" grammatical errors. In fact "ten items or less" is the correct version! Who knew?
I'd therefore stray away from identifying "offenders" on multiple grounds. It's not only potentially obnoxious and can backfire, but also often the offence turns out to be anything but. One of the reasons English is such an utterly fantastic language is its relative lack of rules, and what rules there have been often get thrown away anyway. Trying to keep hold of these rules might have the opposite effect to that intended by destroying the very thing that made the language so special.
There is a good weekly column by Oliver Kamm in the Saturday edition of the Times that's well worth a look for all aspiring grammar sticklers. You'd be amazed at how often the stickler's "rule" is not just "more like a guideline" but even on occasion utter rubbish.