Here's a situation:
The ancient Greeks (and, to a lesser extent, Romans) accepted pedophilic and homosexual behavior as normal. It would be common for an older man to have a younger boy that he would be with romantically, before he married a woman. It was common and accepted in their culture.
Now, the question is: is romantic involvement with young boys moral? Ethical? Was it moral for the ancient Greeks to do it? Was it ethical for them?
Depends. It would all depend on the setting and their culture. Today, ethics/morals as we see it are based on popular views. If most people think murdering is wrong (and most do), commonly, it would be accepted that murder is indeed wrong. However, if one person truly believed that murder was right, and if he was not a sociopath, he would still be prosecuted by the ethical code of the court. It should be safe to say that no principles are everlasting. To say that as people change, cultures change, and ideas change, that moral values would stay ever unfaltering and never diverge, would be in correct. Albeit most peoples views on noteworthy actions are the same (murder, rape, torture, etc) it isn't true to say that we, as the human race, will always believe that murder is wrong, or torture is immoral. Answering the main question, whether the Greek's men/boys homosexuality was just, I face the following questions:
1. What beliefs did the majority of Greece hold, pertaining to pedophilic homosexuality?
2. What beliefs does the majority of the world today hold, pertaining to pedophilic homosexuality?
3. Does the morality of views ever change?
Answers:1. As iago previously stated, back then, it was generally accepted as normal to be in a homosexual and pedophilic relationship with a young boy.
2. Today, while the views on homosexuality have softened, I am pretty sure that pedophilism is not accepted by the majority of cultures today.
3. Also previously stated, morals
can change, and each person's code
will differ, and so any judgment passed onto the Greeks would not, and should not, be everlasting.
Final Conclusion: By the views of today, the Greek's liaison with boys would be viewed as wrong and immoral, but in their time, it would seem inherently right. I doubt anyone can get a more definite conclusion than that.