I believe they, and pretty much everyone else here, thought you were talking about the mechanical shutter that you have to manually slide over the lens.
That's not what mechanical means, but I can understand the confusion.
Those are manual shutters. If it's mechanical, unless you are using a very archaic definition or speaking in a different context it is capable of self movement in some form.
Not that I'd be particularly surprised to find out product marketing on the question is all over the place.
Clicking the mechanism converts the manual input to a mechanical or electrical output.
If you pushed the lead down entirely by hand it wouldn't be a mechanical pencil, which is exactly why you pushing or flipping a plastic cover into place entirely with your own muscle power makes it a manual shutter.
When you type on a mechanical keyboard, what, precisely, do you think is happening? Are you literally outputting a letter by pressing your finger down? For that matter, what do you think a mechanical keyboard does?
Fucking Google it.
I do love having to explain basic terminology to a relatively well educated yet stupendously deaf audience.
Really restores my faith in humanity.
We're not fucking cooked, and the mental infantilization of the population is not complete.
Of or relating to machines or tools.
"mechanical skill."
Operated or produced by a mechanism or machine.
"a mechanical toy dog."
Of, relating to, or governed by mechanics.
You're using the second definition and everybody else, including me, is thinking of the first or third. I would call anything that has a mechanism integrated into it, such as a manual slide that covers a camera, no matter how simple, to be mechanical. A playground teeter totter is pushing the definition, but I'd say it's technically mechanical.
You're welcome for the lesson on the finer semantic details of your secondary language.
Bonus terminology:
"Appeal to authority": A logical fallacy in which it is claimed that a person's expertise in a field is proof of a claim itself. This is a disputed fallacy, as there are indeed certain instances where it might applicable, such as a mechanical engineer describing the workings of mechanical systems, but is always a fallacy when they attempt to use their expertise in one field as proof in another.
You can have a manual input to a mechanical system. For example, pulling a lever to operate a machine.
The typical distinction is whether it uses and translates the input through various mechanisms. Moving a shutter with your thumb is not a mechanical shutter.
Flipping a switch or pushing a button to do same thing could be. The manual input is translated to a separate output instead of the person providing the energy directly.
Did I explain this middle school vocabulary lesson to your satisfaction?
You used to be able to get a mecha for a five cents. Gimme a mecha for a nickel, we'd say. We didn't have actual mecha (because of the war) so we used jam jar lids instead. Now one time Puddinhead, his name was Gerald Brown but everyone called him puddinhead because he had this hat that looked like a pudding cup. I don't know where he found it. Maybe he made it, which, in retrospect, was really neat. We were a little too hard on old Puddinhead. Anyway...