Truer words were never spoken! Insistence and persistent repetition of opinions mean nothing. Without a clear understanding along with actual evidence, one is only voicing an assumption by saying the pyramids were built by an ancient culture other than the Ancient Egyptians.
Maybe I should ask, if a better use of time would be to engage in some actual investigative work instead of hopping whatever band wagon, supporting your beliefs, happens to be passing by. Maybe producing some real evidence, other than just a say so, supporting ones beliefs? Merely voicing unsupported opinions does not equate to actual research for the truth. History has demonstrated a truth found in both mainstream and alternative theories, erroneous opinions repeated often enough have the bad habit of becoming fact in the mind of the opinion holders?
Which brings us to the next question: What constitutes proof beyond a reasonable doubt? What evidence is available beyond any reasonable doubt, supporting an antediluvian civilization being the builders of the pyramids?