Is someone a plumber if they followed step-by-step directions to replace the flush valve in their toilet, without understanding how any of it works, or what the parts are for?
Where is the boundary? To me, it boils down to two things - do you spend the majority of your work time on it, and do you understand how your tools work? The former is necessary because even though I was an electrician’s apprentice as a teenager, and can explain how pretty much anything electrical works, it’s not my primary job, so it would be weird to claim that. The latter is necessary because otherwise, you’re diluting the title for those that have it. I can explain how max() works (or at least, an implementation of it). I can give pros/cons for functions.