There wasn’t any confusion. Their point was they’d much rather pay a monthly fee, because as it is, paying full price to “own” a Stadia game is ridiculous because Stadia is going to end up dead like most other google services and all the games you “own” will likely disappear.
The problem is that Valve doesn't have a history of just cancelling their products and shutting their customers out. Google does, and an extensive one. So when they offer a service where you can buy software and said software will only work for as long as Stadia is around, I don't trust Google that service will exist in 3 years. And once it finally dies what will Google do? Give everyone AdWord vouchers?
It's comparable to the lease you make with Valve with the expectation of Steam being around forever.