You can absolutely claim either that you're too stupid to understand what you're saying or that nothing you say should be taken seriously. That's how Rachel Maddow won a defamation case against her.
The bar is ridiculously high. Like, we all know these people acted with intentional malice. It's clear as day. But you have to clear all 4 hurdles to get your case off the ground.
You're misusing the word grifter. Bauer may like attention, but who cares? He's not making any money by engaging with fans. Colin Kaepernick converted his fledgling NFL career into a huge contract with Nike to pretty much race grift full time and occasionally pretend that he wants to play football again but that the whole league is blackballing him. He's now moved on to starring in documentaries which compare the NFL draft to slavery.
When Bauer reaches anywhere near those heights, you might have a point, but he hasn't, so you don't.