The way it was explained to me when I was a "noob", the plumbers are at the top of the "contracting food chain" - ie they can cut what they want, and run wherever they need to.
Electricians are next.
HVAC guys are lower, then cable/phone/security.
Rockers are supposed to cover it all up so you can't see it, but somehow they're below the painters and trim carpenters, who hide the sheetrock; they're also below the framers who provide the wood they hang the wallboard on.
I also just write it up to them wanting to feel more important.