Or rather, they want
their "shill picks," and see any other perceived "shill pick" as unacceptable. There was a 4chan thread when Terry was announced where people were livid about SNK's "shilling" and called people to action, directing them to dislike all their YouTube videos and contact them directly to complain, as though Terry isn't the most major character in a long-running and famous fighting game series. Why? Because it wasn't Edelgard instead.
This isn't to say that this is how all Fire Emblem fans are, or how any fans of anything are--these are just hoodlums on 4chan being hoodlums--but it was a hilarious example of how a lot of this just boils down to "The character
I wanted isn't the one we got, so I'm going to complain." Nothing wrong with being disappointed, but ranting about it, let alone organizing campaigns against entire companies over it, is where things get ridiculous.
That's why I try to take a more detached view of things and find excitement even when there's nothing for me to personally be excited about. I thought Ryu, Cloud, Bayonetta, K. Rool, Joker, Banjo & Kazooie, and Terry were all awesome, despite not having ever played a single game in any of their series, all because they're crazy picks that made a bunch of other people happy and added something new to the game in some way.
As opposed to if we got an eighth Fire Emblem character, or another Pokemon.