No, that's not true. I explained it already and I'll reiterate:
If the design team decided that they felt it was ugly to have a port along the edge of the mouse and designed the port in the bottom to address that aesthetic concern it would be form over function.
If, however, the design team was concerned with customers using the mouse as a wired mouse for a technical reason, such as, wanting to preserve battery health, that's a function over form decision.
You're attributing the form over function conclusion to Apple without enough evidence because you don't know what decisions guided their design.