And I may not know what this question is, actually; I may not be able to print out my current guess nor my surrounding framework; but I know, as all non-moral-relativists instinctively know, that the question surely is not just "How can I do whatever I want?"

I'm not sure you've done enough to get away from being a "moral relativist", which is not the same as being an egoist who only cares about his own desires. "Moral relativism" just means this (Wikipedia):

In philosophy, moral relativism is the position that moral or ethical propositions do not reflect objective and/or universal moral truths [...] Moral relativists hold that no universal standard exists by which to assess an ethical proposition's truth.

Unless I've radically misunderstood, I think that's close to your position. Admittedly, it's an objective matter of fact whether some action is good according to the "blob of a computation" (i.e. set of ethical concerns) that any specific person cares about. But there's no objective way to determine that one "blob" is any more correct than another - except by the standards of those blobs themselves.

(By the way, I hope this isn't perceived as particular hostility on my part: I think some very ethical and upstanding people have been relativists. It's also not an argument that your position is wrong.)