This is a big change, which is evoking some powerful reactions in people - it's pretty obvious that a company might want to get some distance between its brand

This is a big change, which is evoking some powerful reactions in people - it's pretty obvious that a company might want to get some distance between its brand and the maelstrom. They can always come back later, when things calm down. This way, if nothing happens, they can always come back silently (or spinning the story in a way they want). If some PR disaster happens, they are safely away from it. For me, this was to be expected and is a testament of how important Twitter has become in the marketing world that it isn't bleeding out advertisers even quicker.