everytime one makes a value judgement one is effectively making a critique, which need not be negative , indeed the very act of praising these ads (or not) which is what this thread is about is a criticism of them, and indeed to poke fun at perceived American values (which may or may not be accurate) using a sterotypical represnetation of a Greek Yiayia (again which may or may not be accurate ) essentialy involves a critical process of both.
We ln the UK did of course have a sterotypical Grandmother portrayed in BT Adds by Maureen Lipmann in the 1980's
http://www.youtube.com/watch?feature=endscreen&NR=1&v=H1O3bWgRbWE