I've noticed that as well. I think it's because turning up one's nose at a game and harping upon its flaws and mediocrity make one seem much smarter and knowledgeable about the business than the developers, who obviously have no clue as to how a "good" game is constructed. In some gaming circles, liking a game makes one appear to the hard-core cynics as puppy-like, fanboy, or sheeple behavior. Only those who can articulate how poor a game really is are, like, the "real" gamers.
Or maybe after a few weeks the initial wonder and awe wears down and you start to remember the annoying bits - like the "Decompression in progress" sequence in ME, interestingly over which I haven't seen anyone complain yet for some reason. And then come the "How to design games "properly" discussions.