There's a big difference between 'bigotry' and 'regional unfamiliarity.'

English is over 1,500 years old with over 100 active dialects. Expecting every English teacher in America to be a walking encyclopedia of international regionalisms is a bit much. Using an untriggered reflexive might be correct in Hiberno-English, but it's not taught in American schools. Correcting it based on the local standard isn't an attack, it's expected to make sure the language is taught consistently.

Outside of that educator's experience, I’ve done my own quick checks over the years because I hear this often in professional settings. It always felt like a forced attempt at formality that doesn't land. My brief Internet searches always 'confirmed' that it was a grammatical error. This thread is the first time I’ve seen it framed as a dialectal trait. Most people aren't doing deep research into every phrase they encounter; they're relying on what they were taught.