Why YSK?
The first person who typed “should of” probably heard of it in real life that was meant to be “should’ve”, they typed “should of” online and readers thought that it’s grammatically correct to say “should of” which is in fact wrong and it became widespread throughout the years on Reddit.
I hope something could start to change.
… they are wrong.
It’s okay for an entire region to be wrong. Look up “how the Southern States were generally super racist” and see how pervasive wrongness can be and still be wrong.