why the BNP's members should not teach

On Nick Campbell's show this morning on the BEEB, the topic was the BNP's right to free speech and the problem that causes in public service and particularly education. His show always has good open discussions, unlike Dimplebutt's grandiose subterfuge Question Time.
One thing was unfortunately not raised as an issue and I've just thought of it.
What if you are a minority child [it's taken for granted that you've been insulted because of who you are] and you find out that your teacher is a BNP member.
Remember, this is a temporary but regular guardianship (in loco parentis), so teachers are obliged to take care of all children.
What is a child to do?
Can s/he change class? NO.
Can s/he avoid being scared of that person and what they'll say or do to him/her, or how they will mess up his/her school career?
It's enough to make an 8 year-old pick up smoking.