That's surely just an over-reaction to people being told "and I" in response to a sentence like "Mary and me would like to welcome John to the team". You can't win.
As a kid, you get 'Me and Mary' as the subject corrected to 'Mary and I' for reasons of both grammar and politeness. Some people don't understand or remember the compound reason and just use 'and I' everywhere.
Of course, prescriptive grammar is for the birds, anyway.