No self-respecting punk band would write "When September Ends" or "Blvd of Broken Dreams" much less whore themselves out on every MTV special, teen bop magazine, and whatever else.
To an extent, punk cannot be defined. It is, pretty much lack of definition, or a choice not to allow oneself to be labeled. At the same time, what Green Day does these days is just corporate whoremanship.
I liked American Idiot when it came out, and I hate to be one of those people who put down bands when they get big, but the media saturation of Green Day just makes me sick of seeing their mugs and hearing them play. They allowed themselves to get overexposed. Not got for any band.