The example you give and its answer follows a line of reasoning that leads you to an interesting conclusion, that's the point of thought experiments.
What I was saying is more akin to answering your example with:
"Oh no you can't! There's not enough steel on Earth to build such thing and even if you had it, it would require an EEeEeeenOOOOrrrMMMoooUUUusss amount of energy to put in place ;)."
That would be quite a moronic interpretation of the problem that completely misses the goal of said thought experiment, which is, well, to make you think.
The difference there is, I think, that the pragmatic argument of "not enough steel" doesn't prove the non-existence; while the argument about "there are no truly rigid bodies" does.
I haven't seen that Veritasium video, but it sounds like it makes the exact same point. It's not that we haven't found a material that's rigid enough; it's that a rigid disk is counter-factual to begin with, even in non-relativistic conditions.
What I was saying is more akin to answering your example with:
"Oh no you can't! There's not enough steel on Earth to build such thing and even if you had it, it would require an EEeEeeenOOOOrrrMMMoooUUUusss amount of energy to put in place ;)."
That would be quite a moronic interpretation of the problem that completely misses the goal of said thought experiment, which is, well, to make you think.