Oh, he's a total troll. That doesn't mean that his trolling isn't a little too close to home. The NAACP just released a statement that they are totes cool with Dolezal, which is what they have to say. But you KNOW that they are fucking PISSED.
The NAACP is a private organization (assuming its private) and can handle its own matters as they see fit. Remember, America is all about letting private organizations do as they wish, without interference from any other institution (government, state, city, etc.). I am not going to questions NAACPs response to this. They can do as they want.
I do not think that troll was advocating that race is a social construct. Though, he does make some interesting points about other social constructs such as culture and ethnicity. I mean, if I moved to Russia, would I consider myself Russian, even though I was born in America? Could I honestly call myself a "Russian?" Or what about people that convert to other religions? Obviously, its near impossible to do that with race, since you can't change the color of your skin. But it is an interesting thought experiment about how people identify with different cultures and/or traditions when they move from one place to another.