I've never had a bump where I was handed an itinerary before I was already committed to taking the bump. Thus, in almost every case, you have to rely on what the agent is promising you. So no, I have no sympathy for the notion that this is the OP's fault because he needed to carefully read a new itinerary (which typically you wouldn't see in the first place). Specific promises were made to him by an authorized agent of the company. He was entitled to rely on those promises in the rush of the bumping/boarding process.

Also, the OP was promised C+ seats on the flights and didn't get them. It's way off base to suggest that someone needs to pull up a flight map on a phone to double check that the seats actually are C+ after the agent specifically said they are C+ and they are near the front where you would expect C+ seats to be.

But of course, Delta just can't do anything wrong for so many of you. To the contrary, the airline's front line personnel screw up a lot, and some of them actually do engage in shenanigans for the benefits of friends and family, and yes, some of them will lie to you. You're putting your head in the sand if you think close to 100% of front line personnel in any large company are trustworthy. I have over 25 years working in a role (including a stint at Delta) where I have seen first hand that this isn't true. A significant number of people at any level are untrustworthy, unfortunately.