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.
Crazy thing is, it’s getting widespread acceptance, and will probably accepted as grammatically correct in a few years.
A bit like how putting “would” in a third conditional if-clause has become standard in US English (“We wouldn’t have been late if we would have taken a taxi”).
I know language evolves but it doesn’t stop my left eye from twitching whenever I hear it.
Not until the definition of the word “of” changes. It is not a synonym for the word “have,” nor will be anytime soon.
Perhaps, when speaking, accent, mush-mouthed laziness, or plain ignorance will confuse “should have” and “should of”, but one is objectively correct, and one is not.