I'm sorry, but we can theorise about Stonehenge for years.
As with the paranormal, I do not accept that there are 'experts' in this field. What are they exactly experts at? Guessing and presenting theories based on observations made? We were not there, and with a general lack of any records to use as evidence, we can only present our interpretation of our findings. That does not make us an expert - it makes us theorists.
Unless we can travel back in time and ask the question in person, like the great Pyramids at Giza, we will never know the true answer as to 'why' or 'how' our ancestors built them..........