I'm just going to add, as a personal observation, that people who do not draw and are not primarily visually sophisticated (though they may be math or music or medical geniuses) can sometimes be easily fooled by the crudest visual effects.

I looked at some of the pictured stones and saw nothing that indicated antiquity. The drawings look modern to me, done by someone with somewhat limited raw talent, in imitation of modern pictures they've seen of both real things and fictional things.

One of the pro arguments was that they are carved in very hard stone, not possible with the tools archaeologist claim may have been available. They aren't. They are carved in the oxidized outer layer of the stones, which in some cases (on stones I am familiar with) is so soft a person could carve it with a fingernail, and certainly with a steel or iron nail, which looks to me like the tool of choice for the style.