His point is that passengers don't care about YOU, they care about themselves! The worry is that unionized FAs aren't as nice as non-union FAs. Passengers don't care how grouchy the pilots are (and they trust the FAA enough to ensure that the grouchiness doesn't impact safety of flight).

(Not my opinion, btw...and maybe not even his. You just asked why people get all worked up over FAs unionizing, and I think this is probably the answer.)