Honest question: Can we call this unfair if it was already laid out as part of their rules?
He didn't say anything "offensive" or "disreputable" to anyone other than authoritarian regimes, and if that's the standard Blizzard is going by they can fuck right off.
The rule as written very obviously (at least to me) does NOT prohibit making public political statements in support of particular political groups and processes, actively and instensively advocating for or against certain policies or parties, using props to do so, explicitly condemning policies of certain governments, being a politician or candidate or pundit opinion-maker yourself and expressing strong political agendas to others, etc. It does seem to cover certain forms of expressing these statements (e.g. profanity and insults would fall under the prohibiting language) but not the political opinion as such.
An explicit prohibition against "offending certain groups of the public" is inherently assumed to include demographic groups but exclude political opinions, governments and individual politicians; so shouting "Government of X is horrible and their leader Y is evil" does not violate such a rule in any way whaotsover; that's legitimate political opinion; it's unalienable right of everyone to believe and communicate such things if they want to. Criticizing and insulting policies and political organizations simply can't be offensive in the way that insulting individuals or groups of people can be; if someone says that a statement of "stand with Hong Kong" or "stand with united China" hurts their feelings, then that's probably their (valid) opinion but it doesn't make that statement offensive or insulting no mater if someone claims that, statements of such format simply aren't offensive no matter what political group they support. "Fight for faith, stand with ISIS" or "Fight for man-boy love rights, stand with pedophiles" are justifiably unpopular slogans which would/should raise some eyebrows but they aren't offensive or insulting.