Power determines morality my point is that power and influence go hand in hand, take religion for example, you could argue that power of religion dictates your moral views.
Also you haven't captured the switching of power accurately in your depiction because you're not measuring the correct level of power/influence of the people involved.
Like let's say you have 33 presidents that all had one moral view, would the power of the 34th incumbent be enough to change public opinion if it was contrary? Nope but if the subsequent 34 presidents supported this new moral view then of course the view would change
On homosexuality my point is, if you were born in a Greek society it would be seen as okay however if you were born in a 19th century Christian society it would be wrong. You see there's no objectivity here it's just boils down to what each society wants, how many people want it and if they have the power/ influence to enforce it.
Let me ask you, does an individuals moral view matter if it's contrary to what society thinks? And if it does matter how can you validate it?
For the murder I'm saying it goes much deeper than that.. There's also how we murder and who we murder. Is abortion wrong? What about euthenasia? Lethal force? Capital punishment?what about animals, do you see how all these factors have no meaning on their own but are purely determined by what the majority of people think? How can you prove something is right if you're the only one that believes it? Doesn't it boil down to mass belief which is determined by power and influence.