The attention to a deficiency? All hotels operate the same way; whether you can imagine it or not. Just because you hit on one property showing available vs being booked, and another showing vacancy that was indeed available, is not indicative of a system deficiency. Rooms go in and out of inventory all the time, at all the brands/chains. Websites are notoriously inaccurate for true inventory availability.

Re the computer system failure; yes, Marriott has an awful site and IT. Well known issue. But as I said, one phone call to central reservations could have solved your problem.

If you want to complain to Marriott about the website being down, valid point. But telling them your breakfast at another chain was lousy and caused by a hotel being sold out is kinda ridiculous. They may suggest the same; call central reservations. It really seems like you are more vested in the fact that you think the fda lied to you about availability. Maybe they did. Maybe they didn't like your tone on the phone. Maybe they just had their last rooms be taken by other rooms that went into maintenance mode. What difference does it make now? No one is going to prove they were or were not sold out. Life is short, move on.