I don't see why we are talking about europe being able to defend itself or whether anyone is going to attack it (although the OP starts on that point it seems like we can leap beyond that...). It seems like the more contentious issue has to do with being able to project power around the world and contain aggressive dictators. Does anyone have an idea what the world would look like if the US didn't have that ability? What would south korea look like? That's the only concrete thing I can think of. So the question seems to be, should Europe shoulder its share of that, or can they just shrug it off as "world domination aspirations"?

Whether you agree with the US's current attempts is irrelevant, unless you want to argue that all such attempts are necessarily bad in the way you argue they are.