Let me get this straight.
Well Pat.... ya didn't. He didn't attack the newbee. Nor have I.
The question is a valid one. The fact that a general class licensee asked it is the point of contention. By the time one is a General he should know what a filter is and does, at least the concept !
That the testing for this knowledge is non-existant is the point. That's how I read it.
So the answer to Don's original question is No. A general class operator should not be asking that fundamental question. That he is, indicates a fault with the technical requirements for a license not the newbee himself. After all..... he followed all the rules and proceedures to get his ticket. Obviously, that path has changed over the years.