You don't need to be able to build a capacitor from scratch in order to understand how they work. Furthermore, electrical engineers don't have to build capacitors from scratch during job interviews to prove their competence.
No, but there's a level of the EE tech stack where you do need to understand (and have the ability to build) the level below. I don't need to know: how to construct a transistor, build a logic gate, build a look-ahead adder, construct an ALU, CPU, computer hardware, write assembly, or write a compiler to do my job (although the last couple start getting close enough to my bailiwick that I think they're useful).
I'd expect that something basic in an EE job could be "draw the core part of an oscillator circuit, then we'll talk about the principles of its operation". The discussion would end up going into some properties of capacitors, why they chose that exact form of oscillator, expected use-cases, etc. The behavior of the object lower in the "stack" becomes important, and so does a real understanding of how they work. Of course, actually requiring them to build one would be ridiculous.
>>I'd expect that something basic in an EE job could be "draw the core part of an oscillator circuit, then we'll talk about the principles of its operation".
Sure, but that's the equivalent of drawing a diagram that explains how quick sort works, as opposed to implementing it using real code. Most companies demand the latter during interviews.
The places I've interviewed (a few big names and a few small ones) either wanted something pseudo-code-like (on the whiteboard), wanted an explanation of the algorithm (potentially with some clarifying diagrams or code), or actually provided me a computer with an IDE.
