None of that is true. Well, except everything before "Oh. My. God." In truth, this is one of the stupidest things people have gotten upset about in Hollywood this year, let alone this decade (and the one before it). There are a lot of more important things to get pissed about. Such as how women are portrayed in films and TV. Or representations of people of color. Or the fact that most of the crap they put on TV looks like it was written by a 5-year-old missing half a brain. But this? Please. Grow up.
And, yes, contrary to what some of a different political persuasion than myself might say, I would not have cared either if the bust was Barack Obama, except for the fact that there are almost no black people in Game of Thrones (season one) to begin with. Putting him up on a spike wouldn't make any sense, and I might get a little annoyed at that if I actually noticed it. But would I have? No. I didn't notice George Bush either, and I don't even like him as a President.
That said, I don't really know where I stand with the producers' rational for why they used a replica of his head. Is it possible they couldn't afford to rent or make a whole bunch more body parts and heads? Maybe. Could it also be a veiled political statement? I guess. But that would assume David Benioff and D. B. Weiss are stupid enough to a) put it in their movie knowing some place like Big Hollywood will scrutinize everything they do, and b) mention doing so in the commentary. If you wanted to make a political point, I'd think you'd take the moment to say something in the commentary. Maybe they're that dumb, but I find that hard to believe, and I don't feel like making that judgment right now.
So I will officially file this in my "stupid crap that the world got upset about" bin. Do with it what you will.