Dissolving the Fermi Paradox

This contextualises the issue and brings up the questions you mention. Without this imposed meaning the questions go away.

People like giving meaning to the unknown.

The ~50% probabilities from the paper are not fundamentally more founded in reality than "Did another planet in our galaxy develop intelligent life yet that attempted to communicate? I don't know, so let's assume 50% either way. Therefore, we are alone with 50% probability." Should that number be 50%? Or 10%? Or 99%? You're choosing some prior there. So does this paper, and the priors chosen gravely affect the result. Of course, the paper has more intricate math and more solid reasons for their priors, but fundamentally it is still just assigning almost arbitrary probability distributions to parameters that we have no grasp on. Specifically (see my other comment), the numbers that they get primarily depend on the choice of prior distribution for the abiogenesis rate, which overshadows all other parameters. It has such massive error bars (>200 orders of magnitude by their own account) that arriving at a concrete probability (in the way that you understood it when reading the paper) is somewhere between misleading and a lie, because it's more or less just a projection of that prior into a single number.

In other words, I'm convinced they could have easily arrived at probabilities like 0.1% or 99.9% by reasonably varying their prior distribution for that parameter alone.

This makes intuitive sense too — an early Great Filter simply has to stop life from occurring, while a late Great Filter has to deal with the complexity of preventing life from doing what it does best (surviving and spreading in a “Life finds a way” style). Concretely, an early Great Filter has fewer variables it must affect than a late Great Filter. Like the paper says, we are probably alone, but there’s little reason to be alarmed about it.

And if you happen to believe that AGI and a Singularity are the inevitable outcome of intelligent life, the case is even stronger that we are the first, last, and only. However powerful the Great Filter might be, it’s unlikely that a super-intelligence would succumb to it.

Not necessarily, because the principle collides with observer bias in this case. I don't think it's valid in this context.

"There are so many other explanations for Fermi Silence"

Of course. I'm not concerned about the explanations themselves though - more about the emotional dimension; the attachment to the underlying idea. Lots of people seem to yearn for the ETI to exist at all. They'd be fine with any of the explanations you mentioned to be true, as long as the core concept is protected.

"None of this requires aliens who will teach us anything, one way or the other."

My point is not that they would, or that it's a logical scenario. My point is that humans exhibit a strong cultural need for this type of narrative.

I'm interested in this anthropologically, so to speak. I don't really care about the actual aliens (or the lack thereof).