the CD4082 is sold as an AND-gate.
I would not know, I abolished the use of the CD4xxx slowpokes ages ago, but for the sake of this, the 74HC08 is "sold as an AND-gate"

You can also call it "negative Or" ... in this certain application the input signals are of negative logic, means that when a key is pressed the according row is low
which makes it something that IS, not something "that can be called" a negative OR.

the gate is an AND-gate
Incorrect, "the chip is an AND chip, the gate is not.

that it doesn't work as AND-gate, which is just wrong.
Nothing wrong, it does NOT work as an AND gate, if you want to state "it works as an AND chip" that is something else.

Erik