You pointed an inconvenient fact about Obama and a lot of people are not going to like that. They could discuss it or flag and run away quickly. Flag and run away is too easy, so that's what ends up happening.
One time I criticized the obsession with Russians. A user went and start digging through my comments to determine that I speak Russian (which I do) and that meant proof I was a Russian shill, paid by Putin presumably to subvert Democracy right here on HN. Which is doubly creepy given that the Russian government deported and persecuted members of my family in the past.