Hmm. Is there an automatic feature for quoting? I cut & pasted for this post, which seems a bit clunky.
Might makes right?
I said nothing of whether it was right or not, but simply the mechanics of how it is done. Whether you intended this to be a loaded question or not, your words come across as a moral judgement on your part while rejecting the right of others to make similar judgements. If you intended your position to be value-neutral, it does not come across that way - nor do I think such a thing is possible.
I would have no problem accepting a theory of absolute morality. It would just have to somehow bypass the inherent limitations of the human condition for me to treat it as valid, which is a rather tall order.
Yes, it is a very tall order. Absolute morality implies infinite capacity. Anything that is finite can only aspire to the finite - and hence a relative morality that will forever be revealing its flaws. As such, I expect we will forever disagree on the level of authority any one moral system can carry. And authority is what lay at the center of my original point, not morality. So, with regard to what I originally addressed, i.e. your statement:
Since it seems that all actions are fundamentally in self interest, why should some individuals' goals take precedence over others?
What other answer would you give other than the ability of some to enforce that precendence?
It is my understanding of the terms that by definition, action would have to be either one or the other .
My understanding is different. The fact is, people who only serve themselves behave differently than people who serve a group. The word "altruism" was created to describe one of the nuances of that difference. So it seems to me that those who come along later and claim the difference doesn't exist demonstrate a lack of understanding, not a philosophical prowess. A quick check on the etymology of the word indicates it may have been coined by Comte. Maybe that alone will help your understanding.
I don't think "philanthropy" is a better alternative. It carries all the same difficulties (especially based on the definition you provided). If altruism does not exist, then the goal couldn't be the well-being of fellow man. The goal would be the well-being of the individual.
And your example of the word "life" does not demonstrate the useless nature of your interpretation of the word altruism. The similar argument would be that "death" is the opposite of life. And, if any death is present, no life can exist. Therefore, since the hair on my head is technically dead, I am also dead. Hence, no life exists.
 Maybe the way to help you understand this is to read the entry on physicalism at the Stanford website. There they discuss the logical difficulty of defining physicalism while at the same time trying to deny the existence of its opposite (i.e. spiritualism). It is a common problem to any premise that defines one thing and denies its opposite. So, I'm not trying to divert this discussion to physicalism, but trying to give an example that possible explains it better than I can.