McCain's a cranky, grumpy old man but he's not a racist
I honestly don't believe that his disdainful and dismissive "that one" description of Obama is anything more sinister than for example the typical barking of a mean old man towards those young whippersnappers who take a shortcut across his property, "Get off my lawn, dammit!"
No intent to dehumanize a black man, just a stupid, insensitive comment, and one that's politically damaging for its own reasons.