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.
It’s because “should’ve” and “should of” are pronounced the same. It doesn’t make sense because they’re just writing what they hear instead of thinking “I’m using the contraction of the auxiliary verb ‘have’”…