Well, Atletico are a special case in that they seemingly play that way against everyone!
Not sure about the onus being on the opposition, necessarily. There are very few teams that can afford to take the game to City, due to the way they play. You say that it's the opposition that makes it boring, but they set up that way because of how City play. Kind of a chicken and egg situation, I guess. You can get at City, but the reality is, aside from one or two teams, most would lose heavily if they did that.
Calling them boring isn't necessarily a criticism, they're just very good at what they do, so most teams haven't got an answer for it. I wouldn't categorize it as a "problem", per se, it just is what it is. A lot of people aren't going to like it. If I was a City fan, I genuinely wouldn't give a shite, to be honest.