Did I say that? No I did not.
Now you put stances and words into play that are trying to label. Why?
In truth none of those sources are 100% verifiably accurate information. But if you feel the need to blindly trust Wiki then who am I to tell you what to believe? But I'm also just as sure you will tell me what I Should believe though.
Don't mock.
Bribery, conflict of interest and politics aside scientists have no reason to actively lie, though secondary/trinary/quaternary sources may mess up something.
Things not being 100% verifiable isn't much of obstacle here.
Just pick most probable things.
A lot of, if not most of descriptions in game are from wikipedia or its sources.
Same with tech and building/unit/resource/improvement placement in tech tree and era targets.
Future content descriptions has mix of wikipedia and other pedia style websites, sometimes primary/secondary sources.
For whatif mod like this one, especially containing possibility of aliens, that can mess around (could be actively implemented trough events, punk style techs and space barbarians), trinary/quaternary sources and their approximation aren't too bad.
Wikipedia is more of low hanging fruit - why hunt for primary sources for whatif mod, if there is readily available trinary/quaternary source in one place, even if it might be misleading in some things?
What would be your sources for description of 175 civics, 941 techs, tens of terrains/features/improvements, hundreds of resources and thousands of buildings and units?
And for beginning of eras, tech placement and building/resource/improvement placement in tech tree?
I wouldn't be surprised, if using wikipedia was tradition since Rise of Mankind started its development or even earlier (Mods before RoM or even game itself).
Basically usage of wikipedia could be as well 10 - 15 year old tradition (since RoM/C2C or even vanilla Civ4 existed).
And for whatif mod sources like wikipedia should be good enough - way more variables are in mod than in our world.