Racism is not human nature.
Not that I want to try and defend Pauline Hanson but racism isn’t human nature? We’re all heavily primed to favour the in-group over the out-group. That is, naturally heavily primed to be so. It takes rather a lot of cultural training (aka, bringing up a child) to get to the sort of free and easy interaction with strangers that we manage now.
It’s just fine to say that we shouldn’t be racist, that we should struggle not to be and all that but to deny that it is part of the basic human toolkit it ludicrous.