Would you like it if they tried to impose their sense of morality on you?

Actually, they do. All the time - mostly they are liberal.

What morality judge in the sky decides when it's OK to tell a culture that it has to follow someone else's rules?

There is none. We should sit back and allow whatever atrocities take placed in the name of culture to happen without interjecting. Perhaps we should allow ISIS to drown Christians in cages and cut their heads off because this is part of their cultural heritage...