I think these conversations are fun to have, even if this particular point is a little stunted. Yes, today's "punk" kids are just buying into a sanitized, corporate, censor-approved mimicry of the original in the same way that sk8ers 15 years ago stopped tearing up their own normal clothes bailing from their boards and started buying $80 baggy jeans from mail order catalogs that also sold skateboards, decals, and sex wax (for lubricating rails and curbs).
Let's take it a little further. Why would the original punks (arguably) not have shopped at Hot Topic and listened to Avril Lavigne? What's wrong with major labels and national chains? There's an anti-authoritarian bent to old punk that extends to "suits," that is, corporations and their soulless, vampiric boards that take things that are fresh and vibrant and raw and sterilize them, wrap them up in pretty packaging, and sell them to entitled suburbanites looking to irk their parents and earn a little hardcore cred.
Admittedly, my experience with punk is limited. Nevertheless, I think I can say defensibly that punk was anarchistic, that is both anti-authoritarian and anti-capitalist, but nobody nowadays wants to admit that they ever enjoyed or sympathized with such sentiment. It was this intellectual underpinning that bestowed all the trappings of the aesthetic with "a point," and separates old punk from the shallow, sterilized affect hawked at Hot Topic. At its best, punk was about snapping people out of their consumption-induced haze, about shocking people into waking up and looking at the world around them with clear eyes. Sure, the guys from Green Day might write songs that are critical of George W. Bush, but when the music is buffed to a glossy finish and released by Reprise Records with a mountain of manufactured, overpriced swag, it's just good ol' Starbucks and Apple Computers liberalism, not the gritty, half-smirking, half-sneering, violent thing that punk was.
I would also like to point out that the political lobotomy that punk suffered hardly happened in isolation. What ever happened to the cowboy hedonism and permissiveness toward drug use of outlaw country, and politics at all in rap music? What genre out there is expressing any actual political dissent, other than the occasional country tune supporting orthodox Republicanism or "punk"/rap song supporting Democrats? The only one I remember is a Rage Against the Machine video ten years ago supporting Ralph Nader.