That's not a branch; otherwise you would have an infinite (or impossibly large) number of branches for just that one line of code. A branch is when you execute one set of code upon a given condition, and another if that condition is not met.

I didn't say every number is a different branch. But on many processors, divide by zero triggers an interrupt. That's semantically the same as a branch.

It depends on the language. In C it is not a branch because division by zero is undefined and not a path you consider. In Java you can argue that there are two branches. One branch that throws an exception and one that does not.

No coverage reporting library will attempt to tell you that kind of coverage. You are essentially in violent agreement with the op but turning it into an argument by using different words for the same concept.