Fair or not, it wasn’t a thoughtful question. You can tell in the way it was asked it was more of a statement than a question and the reporter wasn’t interested in JB’s answer. It was a, “hey, you guys suck at the end of games. Just thought you should know.”
To the point about the way JB treats the media; why be nice? They’re not friends. They’re happy to write nice things when things are nice. They’re eager to write crappy things when things are crappy. They wouldn’t hold back from criticizing him in print or on radio shows. Why would he hold back criticizing them in press conferences? Media members who complain about JB being thin-skinned are thin-skinned themselves.
Questions can be both fair and uncalled for. It might be fair to say your mother-in-law is fat. That doesn’t mean you say it.