I didn't see it but have heard about it. It strikes me that Ferrer is either now beginning to show his age or he's just playing too much tennis just now, maybe because he's desperate to hang onto his ranking?
My own feeling, based on watching him, is that he's playing too much. He looked jaded to me, almost from the start. I think most of us know, just from every day life, that it's easy to get annoyed/frustrated when you are tired, and that is how it came across. He did have a point, but he really did lose control as well. I wasn't shocked, but just a bit surprised. I don't think I'd ever heard him swear until last night.
Coincidentally, does it surprise anyone else that a Spanish player would swear in English? Surely he could have found a Spanish expletive to use, if only to avoid being warned.