This evil moron who grew up rich got this random cashier fired from Home Depot for a social media post. She and her followers are now reveling in it, saying FAFO. Someone has to end this feral shit.
It's one of the most unfortunate things ever, but calling presidents by the title after they leave office has precedent back pretty far. It's not new for Trump. One might argue, correctly, that right wingers are hitting it with a bit too much emphasis in some intangible way... but it is correct to call him that.