I know you're being tongue in cheek when you make that comment, but one of the more important realizations a person can make is that their personal opinions are biased.

This is however, a completely different question to how correct their opinion is. Judging that is a whole different ball-game.

Do it one better and realize even your own culture is biased and largely arbitrary and then you will really have a broadened POV.

I don't subscribe to the notion that all cultural values are of equal value, or are even worthy of respect.

Just that people tend to not see bias when it agrees with their personal notion of truth.

How can you be tolerant of culture without being tolerant of cultural values?

I'm not tolerant of a cultural value that virgins should be thrown into volcanos to ensure a good harvest. There are plenty of others I am not tolerant of, as well, such as the cultural value that some groups of people are subhuman.