I mean, maybe you should? Like... everything has a spell checker now. The browser I'm typing this comment in, in a textarea input with ZERO features (not a complaint HN, just an observation, simple is good) has a functioning spellcheck that has already flagged for me like 6 errors, most of which I have gone back to correct minus where it's saying textarea isn't a word. Like... grammar is trickier, sure, that's not as widely feature-complete but spelling/typos!? Come on. Come the fuck on. If you can't give enough of a shit to express yourself with proper spelling, why should I give a shit about reading what you apparently cannot be bothered to put the most minor, trivial amount of effort into?
I don't even associate it with intelligence that much, I associate it far more with just... the barest whiff of giving a fuck. And if you don't give a fuck about what you're writing, why should I give a fuck about reading it?
Of course, if you do have automated systems setup to correct everything, then by any means, use them.
I see it now as the person respecting their own time.