According the the Washington Post article the connection with those people who wanted to bring in banners and sticks (to hold up signs) to Occupy DC is shaky, considering how the Occupy protests are loosely organized. Regardless, if something inside one of our many cultural institutions upsets or angers you, protest outside! Working and studying (I did take a museum class or two) in the various museums in the DC metro area, I can easily see how something on display can be damaged beyond repair by a large group of people with prohibited items who don't intend to destroy anything.
Even the regular crowds, slowly damage things by shedding hair and skin, and raising the humidity levels of exhibit spaces. There is no need to accelerate damage by knocking into something, accidentally having a sign catch on something, or getting a mass of people press pass ropes or over barriers.