I think it makes sense that in all ages a flat surface for whatever purpose was esssential just as it is today, by why so many people associate it with a form of worship or sacrifice is strange. If you killed and prepared a beast on a flat stone then I would imagine 99 times out of 100 you were doing it for practical reasons and nothing 'ceremonial' or otherwise.
I totally agree. The words "ritual" and "ceremony" are bandied about far too often, I think. My life is not dominated by religious activity, so why should I presume my ancestors' were?