Kraft Singles are only about 50% cheese, so it's fair to call them "not cheese".

You can get process cheese that is actually cheese from brands such as Boars Head. The "process" part just means there's an emulsifier added so the cheese doesn't break when it melts. Despite the sciencey name, there's nothing bad about emulsifiers.

https://www.seriouseats.com/whats-really-in-american-cheese