If you can't make a moral judgement about other people just because they are different from your culture, you are both setting them apart from you as a human and saying that your morals have no values.

There are some viewpoints like which is the best kind of bread that you can leave to personal taste, but if you view something as evil and let others off for it just because they are different then you might as well have no morals

Edit: Also your insinuation that I find cheating bad only because I'm some kind of White Knight is uncalled for. There are certainly Thai women that cheat, but it's not part of their culture to treat it as a standard and necessary part of business. People will make mistakes or just be bad people, but normalising that is not ok