Was a really uneducated decision. I get that he didn't necessarily mean harm, but we all can cause harm without intending.
The posting "Why I can't joke with a friend" is also a sign of this. I'd rather him have been apologetic than try to defend himself, because an educated person regarding blackface and racial stereotypes would either think twice about doing it not to cause offence, or far better not want to contribute to racist stereotypes in this way not simply to avoid looking bad to the public but because you care.
That comes from learning so I can get why he made a mistake. Sadly when it comes to race, when many make mistakes we go on the defence.
That being said, I don't think banning him for 6 games is the solution as goes the so-called expectation of the FA about "racial abuse."
I also don't think he should be "brainwashed" as I think some fear with the term "educated" as there should be room for dialogue. That's a healthier way to address this than force him to agree or ban him.