How is using an already paid for computer giving more money to Apple?

They treat you belong to community, and use your appearance in hidden ads as "just another consumer choose A.. products".

Even if you will intentionally hide all logos of A.. from A.. products u use, their design is very distinctive and widely known, so even looking on Xiaomi most people will think it is A..

Plus, A.. products usually deep integrated into their infrastructure, I mean A.. Wi-fi router, A.. printer, A.. speakers, A.. interfaces (Lightning), etc.

Simple market economics, really: the more people sell their Apple computer, the more supply there is, ergo its value will decrease, and the relative value of the brand with it. You are doing the inverse of this.