TV/Radio people will sometimes, unintentionally, leave their mikes on. When this happens, the general public may well hear comments that are thought by the speaker to be off-the-cuff, frivolous and simply for the amusement of themselves and their immediate companion. The general public will then, albeit inadvertently, be eavesdropping. Most of us say silly, off-the-cuff, frivolous stuff when we believe that our remarks are not for general consumption. We don't weigh our words that carefully in these circumstances and most of us would be embarrassed to find our 'private' banter out there for all to hear.
The comments may well tell us something about the speaker but we have the common sense to nuance this with the knowledge that he/she did not know they were broadcasting to the world. On balance, this would deserve a dressing-down, a warning, some tips on how to remember to turn the mike off and a lecture on the stupidity of prejudice. But sacking? 'Ave a word wiv y'self.