A man who feels that murdering people is right yells "Murdering is right!" Where as a man who believes murdering is wrong yells "Murdering is wrong!"
This is exactly what we have in a war: each side thinks they are morally right and morally justified in killing the other side.
This is just an appeal to emotionalism using murder to make people choose sides on what is considered moral. Thus it is false by your own argument ... or your argument is false: your choice.
But if I may take a stab I'd say that he tacitly assumed there to be concensus amongst the God's wrt to piousness. So the different gods/different views argument wouldn't apply.
The false dichotomy does not apply just to multiple gods, you could also have all four conditions with a singular god. To avoid it you need to show a link between pious and good. Without demonstration for such a link asserting only two of the cases apply begs the question as well.
But the pantheon was quite and eclectic bunch so I don't see how concensus could be reached, but that's the only way I can make sense of the question.
Kind of like trying to find consensus among people eh? Societies are essentially anarchies where different people agree to different rules for what they consider "civilized" behavior.
But if one then wants to justify the framework itself, they have to appeal to another meta-framework. This is no less of a problem for secularist morality than it is for a theistic framework.
This only counts if you assert some absolute source. If you don't assert some absolute source but a relative source then the framework comes from the individual(s) with each one forming a sort of circle of moral structures that overlap those of other individuals to create a social consensus for moral behavior that is dependent on the individuals in the society.
Is it the belief that absolute morality doesn't make sense outside of the cultural framework one finds themselves in at a certain place and time?
Absolutely ... . What is moral behavior for an individual alone in the woods (whether the tree falls or not)? If it is a man, is he still wrong?
Morality is about the interaction of people, not about some absolute behavior: any specific behavior you name can be moral in one situation and immoral in another, thus it is context not behavior, and context is society.
By what standards to you appeal to when trying to come up with a consensus?
What standard is necessary?
The majority opinion changes as the population changes. So does general agreement. This is how democratic anarchy works.
This is one of my problems with relativism: how do we justify imposing our relative values on other societies, i.e., saying "our frameworks right, yours is wrong."
You don't. Only absolutists "justify" imposing their beliefs on others. They do this by appealing to an artificial source or to the apparent majority (ie the fallacy of the "moral majority" being what someone claims - by absolute values - rather than being an oxymoron).
You can no more force someone to accept another "moral code" than you can force people to become democratic by force. This is part of why the Botch Administration approach to the middle east is doomed to failure (another is that they refuse to discuss things with the "opposition" preferring to demonize them instead so they will never understand what the problem is).
When it comes to cultural values there are two basic options: (1) accept traditional values for the culture you are raised in without question or (2) question all values and judge their relevance to you and society. This later approach is enhanced by education and knowledge, while the former is enhanced by force and ignorance.