I've often thought this about YECs.
OECs might say it is not so much a conspiracy as the dominance of a "materialist" mindset in modern society (i.e. confusing methodological naturalism with philosophical materialism). They can do that since they push their divine interference off to the distant past, for the origin of life etc. This is the approach of the ID crowd, for example.
But YECs do actually have to deny the evidence under our noses on a whole range of issues - or deny its interpretation. So it seems to me they have two options: a grand conspiracy by all the scientists to fake the evidence, or a grand conspiracy by God to put fossils in the rocks, magnetic stripes on the sea floor etc., to "test the faith" of the scientists.
It's all very simple really.....if one can "see" it. This physical creation, including mankind, is terribly FLAWED...
And it all, including mankind, was created this way intentionally, by an inferior (flawed) "god"....that is "jealous" by his own admission...
And jealous most of all of us......YOU and me. Because he knows that we, us, the "Spirit" that is who and what we really are...
are superior to him. So long ago he trapped us in this monkey suit, and keeps us here in this hell hole so he can lord it over us.
The greatest "conspiracy" in the history of human civilization is HIDDEN from us, right in front of our faces...
because the greatest conspiracy in the history of human civilization......IS HUMAN CIVILIZATON.