Engineering a stable social life is certainly rational. I would not take this quote to mean "make random offensive statements to make touchy people leave you alone", but rather "be honest upfront about your beliefs and mental models, so that you can filter out people who react badly to them early on".

That is, it is good to politely and quietly (and perhaps indirectly) let people in optional social groups know early on if you are atheist/religious/vegan/liberal/conservative/rationalist/Klingon, so that both you and they can make informed decisions about the value of group membership.

There are, of course, non-optional groups in which this may be a terrible idea. But those are not generally referred to as social groups.