I'd feel similar, if I was an Espanyol supporter. Remembering how I felt when Neymar and Figo left the club for their own ego (or money) - one word, betrayal.
When players decide to leave on their own, it's betrayal in fans' eyes. When players decide to stay if the club wants to get rid of them, then they're ingrateful bastards who need to be insulted and kicked out.
Just a general observation, how most fans behave hypocritically if it comes to this topic. Respect shouldn't be a one-way street. If fans are fine with kicking players out before the contract ends, then they should be fine when players decide to leave as well.
On the other hand, if I respect the players' contracts and I'm fine with players staying as long as they've signed, then I can also be critical towards them who want to end their contract prematurely.