It is difficult to get a man to understand something, when his salary depends on his not understanding it.

-Upton Sinclair

Sinclair's Razor is a stock hypothesis template for explaining why someone appears to not understand something. Suppose there's a proposition X that has evidence and arguments for it, and those arguments ought to be on balance convincing for anyone who's thought about the question of X enough. But suppose that someone works in a field related to X, and has deep knowledge of all the stuff involved in the proposition X, but still doesn't believe X. What can explain this?

Sinclair's Razor puts the following explanation on the table: This person is pretending to not understand X, or has really convinced themselves that X isn't true, in order to not disturb their current position and its benefits.