I think you misread: GP claimed that PTFE is a type of PFAS, and separately: PFOA is also a type of PFAS. And if PFAS is the problem, it wouldn't be useful to ban specific classes like PFOA if they are just replaced by different classes of PFAS.
I'm not sure about the last claim: it isn't clear that all PFAS are equally bad, so replacing PFOA with a different PFAS might be worthwhile. It seems hard to study, but with Europe banning PFOA, perhaps we'll get some more insight.
Your link does not contain a reference to PTFE and looking at the meaning of the acronyms should provide evidence fluorethylene is not a sulfonate or an octanoic acid.
The manufacture of PTFE may involve generating these as bio-hazardous byproducts and PTFE could be contaminated or even break down into them, but they are chemically not the same.