to be fair, when "to" and "too" is not a typo, its quite insane. especially I sometimes see it from english native speakers, and one just has to wonder "how does this happen???"
Huh?
It's not only almost always a typo (as opposed to the kind of mispelling where the person writing doesn't know the difference between the two spellings), it's also a typo that's trivial to make.
Doubly so if you have ADHD, and ten times so if you have dyslexia. But even for the average person, it's just an extra easy to slip o, and as a spelling looks totally legit at a quick context-free glance (which makes sense, since both to and too are actual words).
Literally the opposite of a mispelling "quite insane".
But there it is. To/too, their/they're, it's/its, should of/should've etc are all transcription errors, not a failure to understand or deploy standard grammar.
How it happens: brain fart. We make mistakes for a lot of reasons, all the time, and it's not always logical, like the "it's" you got wrong while probably knowing full well the right spelling.