Your whole post was about how bad QR and how wonderful AA was

For the QR staff, you turned up to check in with a ticket with zero baggage allowance. This is not anything that QR was in a position to fix since tx. The staff were disinterested, as they should be. ( whether they were also uninterested is another matter ) . The agensts saved you wasting even time byt not pandering to demands for QR contacts since the contact you had was with AA

The agents simply took position that you had no luggage allowace and that if you wanted to check luggage in you needed to pay - alternatively was up to you to get AA to fix the issue that it created

The only airline that was causing a problem was AA by not correctly issuing a ticket

Excess baggage fees are notoriously expensive

If you had purchased a ticket from QR and there was an issue with the ticket, then QR would have been in a position to assist - of course it is also very unlikely that it would have had any problems with issuing a ticket for travel on QR and so the problem would not have existed in the 1st place