This is like saying “When I say ‘that’s gay’, I don’t mean gay as in homosexual, I mean gay as in stupid”.
I think it’s a bit different when the word has been totally abandoned for the previous use. I don’t know anyone who uses ‘lame’ or ‘dumb’ to refer to people with those disabilities. It’s practically an archaic meaning at this point. Gay is still most popular as a reference to sexuality.
Tom Segura nailed it.