Three contradictions in one thread. Wow. That's gotta be a record.
Besides that, DotA cannot be taken too seriously--there's so many tournaments and leagues out there for it now it's crazy. If you ever get a good DotA team together you could literally make a living off playing it if you really wanted to. That's the same thing as saying "people take CS too seriously"--depending on the situation, yeah, maybe, but CS is also a league oriented game that teams such as Team3D make a living off of. Same thing as saying "people take games too seriously"--it's not just a game anymore. To some people, it's their method of getting food, paying rent, and paying the bills. That's like saying "People take life too seriously".