This was a bit scary and some like Curtis questioned the legality of it. However, the good news is that this isn’t what Apple does. The company has since come forward and confirmed that no, they will not hold your Apple ID hostage over missed Apple Card payments. As to why this might have happened to Curtis, it seems that there was a misunderstanding.
Curtis was apparently trying to trade-in his old Mac computer for a new one. Apple typically gives customers 14 days to complete the transaction which involves sending the old computer to Apple. However, it seems that for whatever reason, the trade-in process did not go through and was left unresolved, which led to Apple thinking that they had not received Curtis’s traded-in computer, which then led to them disabling his Apple ID.
The fact that this lined up so nicely with the timing of his missed Apple Card payment certainly did not help, but either way, Curtis did eventually get his Apple ID restored and hopefully he also managed to resolve this trade-in issue with Apple as well.