Sadly, I've witnessed some of this "entitled" behavior, too. On our last trip, one morning we were waiting (at ASMo) for an MK bus in a really long line. We had already missed one bus that was SRO, and there was an
ECV waiting as well. When the next bus arrived, the ECV was loaded, and then the other passengers started to load, to the point that the bus was about to leave.
At that point, another ECV came flying up, with its driver yelling from far away to wait and stop loading. She drove up to the driver and demanded that he stop loading because she was supposed to be loaded first. All of this was in front of a line that would easily fill this bus to SRO, and then fill at least half of another one.
Several of the people waiting in line started yelling at the person in the ECV that she had to wait for the next bus, but the driver stopped loading other passengers and loaded the second ECV. While no one was asked to get off, there were no more passengers loaded after the second ECV (and the 6 other people in her party boarded). But this caused quite an uncomfortable situation as several of the passengers who were left waiting were yelling at both the 2nd ECV and the bus driver throughout the entire loading process. In fact, one of the people who had to wait for the next bus went up to the side of the bus to yell at the woman before the bus left.
Ultimately, it was a terrible situation caused by a person who didn't want to wait, even though the driver told her another bus was right behind him and there were clearly people who had been waiting for quite some time already.
I'm not commenting on individuals' needs for ECVs, but
I know that in my time visiting Disney the number of ECVs seems to have skyrocketed. After spending a significant amount of time on our past trip waiting for ECVs to load on buses, we decided from now on we will rent a car. (I know that cutbacks resulting in fewer buses have an effect on this, but that's not the focus of this thread.) I'm not thrilled with this, because part of the appeal of a Disney trip was being "in the bubble" and not having to drive for a week. But if it means being able to save up to an hour of my precious vacation time every day, then I'll just drive.
In the OP's situation, I would not have gotten off the bus, simply because of the attitude exhibited. I was raised to have respect for others, but respect is not a one-way street.