Whenever the topic comes up I always stress that Mad Men is not for everyone.
Some people, when they have a show/movie/music they like and they hear someone doesn't like it, want to insult that person's taste. If comments like those came up on imdb, no doubt there would be condescending responses along the lines of it being over your head and you should stick with shows about car chases and explosions and blah, blah, blah. That pattern of discussion is the #1 cliche of that kind of forum.
I don't see it that way at all. It's a very particular show. I understand people not liking it. But for those who do, like me, it is a show of a lifetime, particularly that first season.