Good grammar, where I come from, is seen as something to aspire to (hm, to which to aspire), not as something to stubbly refuse to accept.
I see threads about could of and could have almost monthly and still (the same?) people come on and howl that it's elitist to point out it's wrong.
When I lived in countries where I was struggling to learn the language, I was always grateful to people who took the trouble to point out mistakes. I listened and learned, and made sure my children were aware of the rules too.
Nobody is born with perfect grammar, but I think if you are literate enough to be on a forum like this, why not just silently absorb the grammatical rule and improve your written language? I come here to learn as well as debate and I pick up something new almost every time I log on - financial, political, property law, style, new recipes, books etc.
So what's wrong with learning that 'could of' is an abomination?
And dare I even mention rein vs reign??