I've never actually seen a place that differentiates testers in that way, purely black or white box testers, most places I have been at have a variety of work. So I don't know how to put some in a technical box and some not since there is technical ability required in all of it.
But that's just my opinion.
Nothing learns better than experience.
"So as I struggle with this issue I am confronted with the reality that noting is perfect."
That would be a "most likely" in my book. (Ditto everyone else though) If someone is hired to test a database then they would need to know DB stuff, etc.....WhiteBox Testers need to know the language, etc...Automation Testers need to know scripting and tools, etc...Performance testers need to know all kings of stuff.
Manual testers don't usually need these types of specific skills. So am I going to pay the same for a job that takes more skills than another, not if I can help it.
"Imagination is more valuable than knowledge." (AE)