Yes, certain moral issues are relative, depending on the society. That is, they are relative in the minds of the people at the time, that's for sure.

We presently seem to have no problem, for instance, sending off our young people to invade other nations and fight wars on other people's land. Excuses are made to justify it. Opposing it is deemed traitorous by some. I can well imagine, however, a society which would not regard any such action as moral, and I would be pretty much in accord with such a viewpoint....in most cases. I might make an occasional exception. Very occasional.

Our business people also seem to have little problem with the idea of destroying vast numbers of living things in pursuit of their short term profits. Again, this might be more stringently questioned in a society with a more sophisticated view of humanity's moral responsibilities toward other forms of life.