A simple search of “golden rule in other cultures” proves that wrong. It shows up in most cultures in one form or another. Sometimes it’s phrased in the negative form, such as “if you don’t want it done to you, don’t do it to others,” but it’s a common observation.
Oh cool. You did a simple search.
Now go to their FOUNDING documents.
The Torah. The Koran. Tribal areas in Africa. Etc.
Basically, those not like you deserve what they get.