>What if part of my culture is that it is right to try to change other people's "culture"?
you can try, but in here you will fail.
>Sorry if I am going over your head on this; it is pretty advanced thought.
It isn't all that advanced - or in any case it isn't new. Your argument (that you should be allowed to take action to change the prevailing culture because your culture demands it….) is just the argument of the bolsheviks and alinsky. It was responded to robustly by Karl Popper in his work The Open Society (note the irony of GS using that name for his NGO). He argues that when a group tries to disrupt a culture by utilizing the rights conferred to the individuals by the cultlure then that disruption attempt is NOT valid if it causes or is likely to cause (or is aimed poorly at) eroding the rights of the individuals in the culture.
You make it sound like it would be incoherent for one culture to question another. This is not so. There is something like self-referential incoherence in attacking the rights of a culture while using those same rights to empower the attack.