Me and my mouth!

So first it was "bastard" (see 25th June) and now it's "piss".  Apparently Helen Mirren on breakfast television commented on a camping trip she went on with Liam Neeson where it "pissed with rain" which prompted an apology from the presenters, and she was told "we can't say things like that first thing in the morning". Really? Why not? It's yet another word with a respectable heritage going back to Middle English, and indeed further back to Latin.  Who decides these things and on what basis?  I can only imagine that the reference to first thing in the morning is a coded way of saying when young children might be watching, but really - do we think kids don't know these words, and worse?  Just whose sensibilities are we trying to protect?