I thought this thread would be about associates as in professional ones.
That sucks because now I can't share my stories of reverse racism that are good for a snicker every so often (like the time at my Starbucks interview when I was very apologetically told that I had to remove my nose ring for the job, even though it went against the principles of my 'religion'- wtf?)
I'll just add a general blanket statement here since you haven't really provided us with the useable info needed to give any real advice.
What you really should be asking is why it bugs you, or why they think they can display such intolerace. Sure they're your relatives but your obligations really end at your personal relationship with them and any shortcommings in the way they view the world shouldn't bug you. But if it still does, it seems the only way to reduce the impact of their opinions on your personal life is to make sure they know to trust you with decisions you make by making more of the important ones on your own, but first make it known that it bugs you, maybe they're under the impression that you too subscribe to the same narrowminded views that they do.