If there's anyone sensitive to the plight of a second language speaker, it's me. I can completely empathize with the struggle.

It probably wasn't the best way to phrase it and it's likely a losing battle anyway. I've found native speakers (which I believe the person I was responding to was) using this form more and more on boards such as this. Mistakes with uncountable vs plural distinctions are also increasingly common. E.g., "there's many reasons" instead of "there are many reasons".

As someone who spent years helping people with a variety of English problems including grammar, it's difficult to stop. I'll try to restrain this kind of comment to the articles themselves. There it's in the author's best interest to write in a way that doesn't cause the 30% or so of the population with stronger grammatical sensitivities to discount them.

I am strongly grammatically sensitive. And although I am not a native English speaker, I claim that the sentence is grammatically correct. It's just a shortened sentence form. Which is often appropriate on forums and similar.

Hmm... I wouldn't have put the period between "form" and "which" in your comment either. Doing so made your last sentence a sentence fragment.

What's your native language? Your English appears to be at least very near native.

Yes, I was aware of that.

Dutch, by the way.

I'm in much the same boat as you, and I don't think it's necessary to stop; what's necessary is to err on the side of being helpful as opposed to judgmental or defensive.