Complex sentence: Its common abbreviation, TINC, is used humorously to suggest that people should lighten up and not see a conspiracy around every corner, or alternatively as an ironic statement, indicating one who knows "the cabal" will inevitably deny there is a cabal.
Split into simpler sentences: Its common abbreviation, TINC, is used humorously to suggest that people should lighten up and not see a conspiracy around every corner. It is alternatively used as a pseudo-ironic statement, since presumably an insider or someone who knows "the cabal" would inevitably deny that there is a cabal.