Nothing, it's the principle of the thing. I.e. when you make a challenging to evaluate statement, the burden of proof is on the one making the claim.
If I say "Moon is made of millennia old cheese", the burden of proof isn't on you to go create a rocket, fly to the moon, sample it and come with conclusions, but on me, making a difficult to verify statement.
the author has put a lot of unpaid I'm guessing work into this repo -- seems reasonable for the author to demand a bit of work out of any asshole taking a potshot at it.
