Not that this is 100% of it, but there are a lot of butthurt fanboys that are determined to hate anything he does no matter what. Take a look at the actual negative reviews of knives out. Most of them talk about it like it's the worst thing that's ever been made ever and that Rian is the worst human on the planet. There's just so many more positive reviews from the average joe movie goer that it mostly cancels them out.

As per Pokerface, it's on a streaming service that isn't terribly popular so there's a good chance that not a lot of people have seen it yet. In fact, I'm willing to bet that a sizeable percentage of the viewer reviews that are there are from people in the butthurt fanboy group that haven't even seen it.