Those are unsupported arguments - speculation without basis in fact.

There are other satisfying resolutions to the Fermi Paradox - such as the idea that we are locally first. DOOM mongers citing Fermi for support should attempt to refute such arguments if they want to make a serious case that the Fermi paradox provides much evidence to support to their position.

Anyway, I don't see how these count as evidence that the "biggest" filters lie in the future. The Fermi paradox just tells us most planets don't make it to a galactic civilisation quickly. There's no implication about when they get stuck.