Some of these phrases do have useful meanings.
"As I've said before" = Why TF weren't you listening last time?
"Let's park that for now"= Knock off the obsessing about trivia.
"With all due respect" = You're management, and qua management you're as thick as two short planks, now do as you're told!
I reserve my right to be condescending, sercastic and occasionally outright rude. Generally speaking, I'm dealing with idiots, and life is too short to waste time being nice to them.