It is possible that it's aliens. It is possible that it's not. We don't have enough evidence even to estimate probabilities, so anything further is pure speculation. Speculation is a look that wears no better on conservatives than on radicals.

There is hardly a field to be found where young radicals are not promoting evidence for what the tenured consider anathema, waiting for the latter to retire or die and get the hell out of the way. As Max Planck said, "Science advances one funeral at a time."

It is common to insist that the right idea wins in the end, but there is no reason to believe it: every case you can cite in its favor amounts to confirmation bias. The frequency of such examples that first languished for decades, with the original proposer driven from the field, would properly make us suspect that the majority of their also-correct peers remain unvindicated, however many false leads have been exposed. (Hypotheses promoted by women driven from a field make a rich vein of ideas to vindicate.)

Loeb is right about one thing: the notion of "extraordinary evidence" is very destructive. Evidence is evidence. It is always easy to make greater demands on evidence you don't like than on evidence you do, and always easy find excuses to discount evidence incompatible with the consensus of the moment. Every field, to be considered legitimate, should maintain an officially taught compendium of "damned facts", evidence that seems to be incompatible with one or more leading theories. Even when a consensus theory is largely correct, the damned evidence will be the basis of any progress.

Nature doesn't play favorites: it is possible for a consensus theory and all its challengers to be wrong. Evidence against one of the latter is not evidence in favor of the former.