>Wouldn't they have to prove the allegations are false?
That's mostly a US thing. England and many former english colony countries have quite liberal (illiberal?) libel laws that puts the onus of the person making the claim to prove it's true.
>defamatory statement is presumed to be false, unless the defendant can prove its truth
I don't see anything out of the ordinary, and there are definitely some common threads amongst negative reviews.
Wouldn't they have to prove the allegations are false?