"Punk" as a watered-down style trend is not what it was intended to be. (Today's politicians aren't what the founders of their parties intended either.) Punks on both sides of the pond have taken open and aggressive political stances since the 1970s. Politically, punk rock typically espouses leftist political ideals (there are sub genres that are extreme right), and that's that's exactly what the highly conservative and tied-to-a-really-old-church Putin wants to avoid. So, it's not surprising that he's omitting that music as a class.
Here's Wikipedia's list of political punk songs, and it's a great place to get a better idea of what the term "punk" actually means when you're talking about a social, musically-based youth movement and not clothing lines. Just take a look at a few titles, like Question Authority, Police Crimes or I Won't Subscribe to get a taste of why a leader with totalitarian intent might want the message blocked.