The item in question is a glass that looks like a cup.
If I ask why it is a cup and not a glass, the answer to that question would be that cups are made to hold warmth which glass cannot do as well as any preferable material that does it better, which is what a cup would be made of, and so it must be a glass even though it looks like a cup. The problem is when someones answer is "because it's made of glass" which, in a way, is somewhat correct, but not really. Me thinking that the latter doesn't answer my question is apparently why I'm troublesome.
Because I'm not a cup scientist that assumes everything.
The stupid, it hurts! Someone hold me!