Cities can do whatever they want.
You already stupidly argued this once before, unless you are some sort of performance artist pushing the bounds of human absurdity. Either way you are wrong.
Can cities put up Trump posters? Can cities sponsor Nazi rallies? Can cities put up pornography at our parks?
It just takes a moment of actual thought to realize cities cannot do whatever they want and that includes
promoting a racist organization responsible for multiple deaths and destruction.
But I guess you and your proto-human brain couldn't remember all that.