Interesting link but why do they consider that Norwegian rock picture to portray an Egyptian boat? It is the same old "aliens" idea. Academics for far too long gave no credit to native north European cultures - everything just had to come from the Classical world and before that the civilisations of the Tigris and Euphrates. Now of course, a very different world view prevails and similar developments without cross -cultural links (like the pyramids of Egypt and Central America) are now the official creed.
I vote for the middle ground and judge each case on its merits with sufficient evidence of probability, rather than absolute proof, required.