In any case, or is named for a logic operation, not a flow control operation. So, would be better if we used if (or unless) instead of or for flow control.

This is a weak argument, because for lots of things, the documentation was added to explain the behavior, not to explain what the designer envisioned.

The http://perldoc.perl.org/perlop.html#Logical-or-and-Exclusive-Or explains or is useful for control flow purposes, thats as close to an endorsement as you can get, documented behavior that can be relied upon