In my opinion, the idea of Protong-as-a-warning has quite a bit of validity, if only intelligent minds weren't so easily dissuaded from looking outside their own little boxes now and then ...
Where's the scientific thought?
If the world was covered with an ocean any time soon (call it the last million years so we can include every human culture) then there would be obvious physical traces, and salt-intolerant species, including plants, would have died.
First you say "apply both to the same subject" and now you say that's fiction may be "just as valid."
Szukalski's fiction is 30 volumes of text. You pick out that "the oceans move"? (By which you mean "cover the Earth", not continental drift or tides.) What about that human culture comes from a people on Easter Island, after Noah's flood? How is that fiction at all valid? Races derive from crossbreeding of species, again, after the flood? How is that at all valid?
If it's hard to pick the valid fiction from the invalid, then what's the point? Isn't it like looking up the date by randomly picking a day from this year's calendar?