Perfect storm of compounded Thule & Subaru design issues, obscure small print in the manual for a known critical safety issue, REI missing it on vehicle inspection and the customer not reading the entire manual!
I always read the entire product manual for anything like this and check what the vehicle manufacturer says about it. Thule shouldn’t really have a “Quick install” guide for a safety critical item. It invites the customer to cut corners and ignore the rest of the manual. Thule’s at fault here for sure.