Derksen just had had it coming for a very, very, VERY long time. He and Van der Gijp have been totally a-holes to everyone for ages. Their defence is that they're unpleasant to everyone indiscriminately, but I don't see how that makes their constant inappropriate jokes any more acceptable. Because they spread the unpleasantness though, momentum never really built up; but now Derksen has been stupid enough to insult black people (Zwarte Piet jokes are never innocent anymore) in the current climate, and that's why his behaviour has finally exploded in his face. That's also what the internationals have said: this sucked, it's been going on for ages, and now it's really enough.
Being old and out-of-touch is not a redeeming feature; it's a sign. Time for these dinosaurs and their old-timey, white-male locker room talk to eff off, as far as I'm concerned.