I'll start off by saying that your post does call archaeology guesswork if not outright intellectual fraud.
TWRule said:
It relies on a the notion that one is somehow acquiring 'knowledge' by digging up artifacts, when in fact it's the case that one had a story/hypothesis they made up in mind ahead of time (usually some variant of a conventional narrative) and ad hoc explain their findings according to that, or at most deviate just enough to be able to tell some coherent story that the artifacts are explainable through, in any case.
So why not just do "history" without consulting artifacts, if it's going to be arbitrary anyway - besides perhaps that arbitrarily checking our stories against 'artifacts' forces our creativity into (possibly) fruitful bounds?
If there is a "moral" issue, it might be just an issue of how questionable the motivations and projects of someone who wants to go digging, pretending to be discovering truths as they go, so that they might either simply win fame/fortune for themselves, amuse themselves at trivial fetishistic curiosities, or hold their "truth" over the heads of humanity as something that they must accept and regulate their actions by.
(Not full quote)
It's rather hard to read the above in any other way. I'm also confused why you put "artifacts" in quotations. The definition of an artifact is any object that has been manipulated by a human, I don't get how skepticism or sarcasm can be directed towards that. You also seem to have profoundly negative views of archaeologists, looking for personal glory rather than any academic or intellectual standard. I can tell you from experience that archaeology is far from a glorious field and there are far better and easier methods to accomplish that goal.
Your perception of archaeology and science seems to be based on the notion that, as the eloquent Mr. Homes puts it, we twist facts to suit theories rather than theories to suit facts. There are things that make sense outside of the frameworks we currently possess. When data begins to contradict the paradigm we currently occupy, we change it. We are interested in truth, knowledge and the like and are willing to change our outlook and methods to accomplish that end. We've done so numerous times in the past century.
To give you credit, you just described a mix of two early periods in archaeology; Antiquarianism and Culture-History. Antiquarianism proved useful for collecting artifacts, but not much else and has since received nothing but scorn from the community. Culture-History was interested in human history, but lacked any real way to do it. However, these two paradigms were abandoned shortly after WWII and the advent of technologies that enabled us to accurately date objects. This influenced everything in the field afterwards in ways that it would take far too long to describe here. One way was the complete rejection of grand narratives.
Basically what you need to know about the current methods of archaeology is a strong adherence to the scientific method mixed in with a very self-critical viewpoint. In recent periods (basically mid-90s to today) there has been a much increased focus on the individual and mythology. We'll likely only ever truly know about the minds of those who wrote everything down (read Rome, Greece, Egypt etc) because, like I said, they wrote it down. We don't have an attitude that we're always right either; we know our limitations.
As for the use of archaeology? To be honest I'm not entirely sure myself. I know that many see it as culturally and personally significant to know they possess knowledge of their ancestors. I just find it an interesting field to work in. However, it is always useful to understand the past in order to understand the present and try to foresee our future, enabling us to see patterns within our minds that have been reflected throughout history. Just because something doesn't advance our society such as the physical and biological sciences doesn't mean it's useless or worthless. I'd like to point out that we're on a video gaming forum.
Captcha; science. it works.
How fitting.