[i] He has to be foolish.
[ii] They all have to be Englishmen.
(From a Korean English-grammar book)
The book says both examples above are wrong, for ‘have to’ cannot be used for guessing something. But the reason itself seems to be not true, because there are its usages as below. Can the two examples above be wrong because of any other reasons? Or can both be accepted?
This has to be the worst restaurant in town. [epistemic] (CGEL, p.205)
have to: (also have got to especially in British English) used to say that something must be true or must happen.
There has to be a reason for his strange behaviour. This war has got to end soon.
d — used to say that something is very likely
It has to be close to noon.
She has to be the most beautiful woman I've ever seen. [=I think she is the most beautiful woman I've ever seen]
He has to have a lot of money to live the way he does.
The bus has to be coming soon.
There has to be some mistake.