In no way is Zwarte Piet racist. The battle against Zwarte Piet is basically a symbolic battle, depicting the actual present racism in society. People shouldn't be upset about zwarte piet, they should be upset about things like having worse job prospects and getting picked out by the police more often. Instead, they have decided to be upset about zwarte piet. This just drives racism. It's a stupid move.
Also, I'm totally against the notion of people claiming it should be changed just because it upsets people. That's not a sustainable way to act.
I believe that we should respect people’s culture. The Dutch should be allowed to continue this tradition because it is a core part of their national identity. To stop this tradition would be to oppress their culture.
It's not Racist though, it's about a chimney sweep, it's not directly correlated to skin colour at all. You're just assuming it's racist because that's what society tells you blackface is, even though it's symbolizing something completely different.
Let people think whatever they want to think. If you want to prove them wrong, use arguments, not bullshit labels like "racist", "sexist", as if that's an argument in itself. This general offense-taking mentality has created an atmosphere policed by finger-pointing tattletales and whiners.