I strongly disagree. Fighting bigotry is everybody's responsibility and what I would consider one of the most important positive actions anyone can take in society.
Earlier you wrote about being ready to accept homosexuals in society. I think this is a worthwhile effort. I think saying:
does not move towards accomplishing that goal. I think Jonathan hit it dead-on, we should be educating our friends and arresting bigotry. Marginalizing does not solve the problem, it just isolates those who are marginalized.
There is a difference, I think, between fighting bigotry and trying to change people's minds. We can change policies to ensure equal treatment and equal opportunity, and we can change our own behavior, but we have no control over the minds of others.
The champions of the Civil Rights Movement got laws changed and eventually helped pass the Civil Rights Act of 1964, but that didn't make anyone stop thinking racist thoughts. What made peoples' minds change was the way society was integrated as the result of these actions.
In the dojo, we can make sure everyone has equal rights and opportunities, and we can show (and demand) respect for all students, but we can't control the way people think. When we create the right environment in the dojo, people will have the opportunity see the truth and come around. But ultimately it's still up to them.