No-one is arguing against Fred Astaire’s talent, all people are pointing out is that this isn’t a good example of the point. I agree with them, it isn’t a good example that show’s how great Fred Astaire was specifically, because he’s doing something that all professional dancer have the ability to do.

Fred Astaire’s name is basically a shorthand for being a famously talented performer, no one is arguing that he’s not talented. People are arguing with the OP being surprised that professional dancers can do this. It is actually acknowledging how skilled they are and how they do this day in day out.

It’s like if someone posted a video of “look at this musician playing the same exact piece twice and it’s pretty close to being identical”. Of course they can do that, they’re a professional musician and that’s the skill level they have.