Well I think we really need to give Obumbler a pass on this one.
He obviously didn't know who Castro was.
This is not hard to believe. He didn't know the healthcare.gov site wasn't ready, he had no idea his IRS was targeting conservatives, he never knew a thing about fast and furious (although Holder claimed executive privilege? - go figure) no one knows where he was when 4 patriots were murdered in Benghazi, he thinks America has 56, no 57 states? and probably still pronounces corpsman, corpseman (can you believe the commander-in-chief couldn't pronounce corpsman? see, we have to give him the benefit of the doubt, don't we?) And of course he didn't know we might not be able to keep our doctor or our health insurance plan, if we liked it. He just didn't know.
If you look closely it appears he wasn't shaking Raul's hand. He probably thought Raul was a hotel bellhop and was slipping him a tip for carrying his bags (why not, he can print tons more money).
I mean how can the man who considers himself the smartest person in every room be so insensitive as to shake the hand of a murdering dictator whose people have risked their lives, often left loved ones who could not escape Cuba, to escape his tyranny by fleeing to America to become citizens here and consequently subjects of his highness, the Messiah.
Obumbler's answer to everything imaginable seems to be he didn't know, even when he lies he didn't lie, he just didn't know the truth. The only explanation for his shaking Raul's hand has to be he just didn't know who he was or that he was actually shaking his hand or both. That's plausible, isn't it? Well as plausible as anything else he apparently expects us to believe.