There is telling it like it is and there is being rude.
There is no need to start calling people names just because they don't know, and there is no need to get rude either. Yes, SLF are 'cattle' to the f/o up front, but really, you can bring your point across without being insulting.
It helps pax-f/c interaction a lot more if you are a little patient with the people who are asking the questions.
I personally have always thought that once you start yelling insults, you've lost the argument, and you know it.
I try to impart whatever knowledge I have without any condescending attitude, after all, I've also been there before, and who knows, I might not have known something specific either.
:-)
S.