I think the whole idea is that this episode was created just to tick off us viewers is a bit extreme.
I know you all feel an emotional attachment to these characters, and don't get me wrong, I do too. I felt sorry for Bloo when he was adopted by Kip and locked in a cage with nothing to eat. I felt sorry for Wilt when he got his arm crushed and his eye all mangled
and I definitely felt for Frankie in this episode. But like Lauren said, Conflict is more interesting than non-conflict. Their intent was to tell a story, and I'm sure they didn't mean any harm by it.
Besides, Goofball was only a one time character. And so was Bendy. Good thing they were, or else there would be some serious fan backlash XD