Every archeological study. The first note of bias is that the subject was deemed valuable enough to study.
There is no such thing as "value free" science. That idea was discredited and abandoned long ago.
Archaeology is particularly subject to political bias in various forms, usually taken to have some relevance to current affairs, even if on a tacit level.
Things don't even make sense until some bias is applied. Prejudgement is a precondition for understanding. We can adjust our direction based on evidence, but the directions we take are strongly influenced by cultural biases, as are the meanings attributed to empirical evidence.
That is precisely my point. However, this is all we can do.
At best, archaeology is an interpretation or translation of a construction of the past into terms we use and understand in the present day.
Another way to look at it is that the past was no less messy and complex than last week. Will it be easier to understand April 2018 in 1000 years, working through what is left of our material culture alone? Will it be possible at all?
The Stonehenge example is excellent. We can accumulate empirical evidence that greatly helps to control and guide inference. However, beyond the challenges of correspondence to data, there is a vast freedom of interpretation. What Stonehenge meant to whoever it was that built it and used it over the centuries, which might well represent more than one group or culture over the centuries, is lost to time.
To me, what become important in such cases is to try to create a narrative that does the past actors some justice, treats them like humans, not uni-dimensional caricature cutouts. Just because we are alive and studying archaeology these days, does not justify the kind of intellectual arrogance often seen in modern archaeology (20th-21st century).
For many decades, all we knew about American Indians was their stone tools and ceramics. The imaginary cultures archaeologists created out of these technologies largely reduced them to point and pot makers, which is what we knew. And then standard preconceived overlays of economic organization were applied--hunter gather, tribe, pre-state, state, etc. We made up the cultures, the definitions, then fit everything together. Anything that didn't fit was called "ritual item."
As archaeological knowledge progresses, and "scientific studies" of artifacts and sites helps with this, we're discovering that the past was very complex and sophisticated indeed. Some of the flint for those points travelled a thousand miles, as did trade pottery. Hopefully, we are moving toward greater uncertainty in our understanding of the past, because we sure have a lot to learn.