A moral question- Should I do work for someone that has ties to the kkk? The easy answer is "no", but I need work.
I doubt you not working for him/her will make them change their ways. So unless it really bothers you, take the job. Who knows you may change their mind or learn something yourself.
When I was in a similar situation, I applied a mark up percentage to the salary I requested. It allowed me to give myself some justification.
Whether that is an option for you, I don't know.
The position did not materialize, and I did feel some relief at not having to compromise on a daily basis.