The fact that there exist an infinity of fractions between one and two is irrelevant and has no bearing on this at all.

It’s an analogy to help people grasp that infinities are weird. Just like there are infinite numbers between 1 and 2, there are also infinite numbers that aren’t between 1 and 2. Just because there’s infinite universes doesn’t mean one of them must have unicorns, in the same way that the infinite set between 1 and 2 doesn’t contain 3. A common misconception people have is that infinite universes must mean there’s one just like the Marvel universe, or that you win the lottery in one, but we can easily have infinity without including those things.

All of the universes could have our exact same laws of physics and that wouldn’t prevent there from there being infinitely many. They could all have the same guy named Gary. The point is, you could have infinite universes just tweaking one variable infinitely many ways, and there are infinite variables…