Some people have quite rightly observed that the Queen has been nice to some right odious bastards in her time, even inviting some appalling tyrannical shits round to her place to celebrate that Jubilee the other day.
For better or worse, there's a world of difference between international and internal politics. Heads of state are like in-laws: obliged by their position to meet each other and smile about it no matter how they may feel about it. Their subjects are more like neighbours: they can pick and choose which ones to socialise with, and report the psychotic ones to the police.
