Their arguments are legit, but rooted in the old-fashioned way of designing/thinking user interfaces.
In todays world professional designers *must* learn to build dynamic interfaces. There's simply no way around it any more. It comes with the trade.
To say "we skip this platform cause we don't have fixed pixel measurements to design within" is another way of saying "we have got designers who simply refuse to learn modern design work."
In a few years time we need to design interfaces that works both on tablets, car stereos, fridges and friggin' GLASSES, ffs. Tell the world then that you don't want to relate to dynamic interfaces in your work... :D