I don't think its that deep, man. I think its more like: "ha look you made a mistake, here's how it's meant to be written, dumb ass." Like the person above said already: the majority of the time people do this it's a simple typo and they know how it's spelt. So I don't really think adults appreciate being corrected on basic shit.

It's like the people who attack grammar in arguments instead of the core point. I've seen enough people doing this across the Internet to know the reason they do it. And it has everything to do with being a smug asshole and nothing to do with helping.