Even though I don't buy the ol' "our relationships in China in no way influenced our decision" part, at least Blizzard has finally released a statement on the matter.
Hello Blizzard Community . . .
I want to take a few minutes to talk to all of you about the Hearthstone Grandmasters tournament this past weekend. On Monday, we made the decision to take action against a player named blitzchung and two shoutcasters after the player shared his views on what’s happening in Hong Kong on our official broadcast channel.