Only racist people see mixed race people as black. In Africa, your son is mixed, in South America, you’re son is mixed, in many area of the UK, your son is mixed. It’s americans and their racist one drop rule that insists that mixed race people are black. In a similar sense that Nazis denied Jewish people in Germany their German heritage.

You are literally citing a doctrine made up by white supremacist to insist that mixed people are black. Oh the irony and if you’re white it’s even worse.