Many cultures accept many things that for other cultures it may be wrong; for example, Mr. Tomalin explained a situation where once he was working in a place with very different cultural, religious and ethical points of view. Once he was passing besides a classroom and he saw a teacher hitting the students with a ruler. He was shocked by this situation, as for most of us this is an unethical situation. On the other hand, he later found out that in the place he was it was not considered bad hitting students. Also, in religion for example the bible more or less gives examples for how believers should have ethical behaviours in very specific passages.
When we were talking about ethics we saw a video about how cows were slaughtered for human consumption, and it gave different points of view, from vegans, vegetarians and meat lovers. It was a really shocking video, as it explicitly showed how cows were killed and it was a pretty violent way. In this way you can see how people can have different points of view about what is ethical and what is not, because vegetarians and vegans find the slaughtering and the eating of meat very unethical, even one of the vegetarians state that he considers it is "just like eating a human".
We live with ethics everyday, and it is a topic that can be very debatable, but there cannot be an universal truth or ethic, because we all think very different, and if we all think very similar, there might be some people who will not think the same as us. Even if we consider something to be a universal ethical truth, maybe a crazy person might think different.