> Can you expand on this, explain the connection? In particular, why the former (belief) would influence the latter (behavior)?
It's not universally the case, to be sure. If you voice your belief that women are intellectually inferior, you will likely make them feel excluded. In general, there is a relationship between a person's beliefs and behaviors which I regard as self-evident.
> Edit: answer to your second question: I try to be inclusive, I don't believe in drawing lines, at least not when it comes to belief (only behavior).
People tend to act in accordance with their beliefs. I don't think I track your perspective. Do you really believe that, say, a person with white supremecist beliefs, again, as an extreme example, will generally act welcoming toward minorities? You seem to believe, well, as long as they don't explicitly disrespect someone, it's fine. But social behavior is a lot more subtle. People can tell if you hate them.