Sometimes they are genuine mistakes - in haste I often hit the next key by mistake so I put I;ve instead of I've, but I know I've done it. I don't think it's "snitty" at all (whatever that means!), - punctuation errors are rife in the big world out there and we all do our bit to make things right.
My sister used to campaign on the High Street about Pea's and High Tea's on boards outside shops. If people aren't sure about abbreviations and apostrophes, it's better to leave them out altogether!