Yes, kitchen appliance usually means powered by gas or electricity, but if something is powered by gravity, it’s still an outside power source. So that’s what I would say the difference is.

A mortar and pestle is powered by your own movement. A filter pitcher is powered by gravity. So I would so that it’s an appliance because of that. A sieve and a slotted spoon are a harder delineation, since they both are partially powered by gravity. I would say that because they have no moving parts, they are not machines, and so may not be considered appliances, but that’s only my own thoughts, not a dictionary definition requirement. Topologically, a sieve and a filter pitcher are basically the same thing. So that’s a conundrum.