One could explain this by saying there are 3 rules in place here.
"Zero divided by anything (except 0) is equal to 0"
"Anything divided by itself is equal to 1.
"Division by 0 is not permissible/undefined"
Dividing by 0 actually gives infinity as the answer, but infinity is not a number.
So, we have 3 possible answers using valid maths concepts.
So which is it?
No-one knows, so it best to just say that