>If a Bell inequality is violated, then either locality or realism (or simply "local realism") has also been violated.

In other words, it's a violation of classical realism, not a violation of locality.

Why not both? i.e. truly a violation.

Violation of the Bell inequalities tells us certain things. Other things it doesn't tell us might also be true, but that's speculation not derivation unless we have some other evidence to work with.

Locality is necessary for the special theory of relativity. That's why not both.

It seems like a huge leap to use a violation of bilocal (not even local in general) causality as confirmation of even theoretical possibility of human FTL travel