Yes, let's ignore non-native English speakers' mistakes. That way, they will never learn, and we can continue to subjugate them, along with those for whom English is a first language, but cannot speak it correctly, probably because they were never taught that "should have" is not spelt "should of" and that their "they're"s aren't quite there.

> those who try to shame people ... into silence on health-related forum threads

That's a bit overstated. But mechanical_fish is right that that my own choice of words could have been more tactful. That's why I changed "Syntax correction" to "Syntax tip" in the GP.

> For the life of me, I can't understand what you found wrong with that use of "substituting". It's correct. It's clear. It's perhaps less colloquial, but it's hardly inscrutable tech jargon.

It's an issue of standard word meaning, not tech jargon. In the context of what 'muxxa appeared to be saying, his (or her?) use of substituting was exactly backwards.

What 'muxxa said was that caffeine seemed to exacerbate his RSI, and that substituting his morning coffee for tea or water helped. But the conventional use of the verb to substitute is to put or use in the place of another [1].

According to that conventional usage, therefore, 'muxxa was recommending putting his morning coffee in the place of tea or water. That seems to be exactly the opposite of what he was saying in the rest of the paragraph about the adverse effect of caffeine on his RSI.

[1] http://www.merriam-webster.com/dictionary/substitute