Believe me I am stunned. I think they must have assumed "serious" means important and of value. And it is probably the case in their mind. The fact that the word "chit-chat" by the very term means an open invitation to discuss and offer views freely whether jocular or not does not seem to register. And look at the users of the "Serious" tag.
I used to think that nothing in SBF would shock me but i have been proven wrong numerous times. And I still haven't learnt my lesson yet.