On top of that, oceanic crust is all quite new, geologically speaking. Even if something large and oceanic did manage to fossilize, unless it was also in a shallow interior sea, whatever rock it fossilized in has been subducted and destroyed past a few hundred million years.

Exactly. These unfounded absolutes are a sloppy habit, though many of us probably do them from time to time.

Strangely, yesterday I was angrily downvoted for pointing out the same problem with a historical statement ("the world's first paint").

An astronomer, a physicist and a mathematician are on a train in Scotland. The astronomer looks out of the window, sees a black sheep standing in a field, and remarks, "How odd. Scottish sheep are black." "No, no, no!" says the physicist. "Only some Scottish sheep are black." The mathematician rolls his eyes at his companions' muddled thinking and says, "In Scotland, there is at least one field, containing at least one sheep, at least one side of which appears black from here."