[BlackFly]

I imagine because the post is not pedantic but is just wrong. If you want to be pedantic and correct, the symbol 0 represents a real number, an integer, and other numbers. The symbol 0 is not a cardinal (counting) number. Some people consider the natural numbers to be either the cardinal numbers or the whole numbers which include 0. So some people consider 0 to not be a natural number.

As a mathematical entity it doesn't represent the absence of anything. It is just a symbol that has certain properties associated with it. There isn't a hole in the real number line where 0 should be: there is a number there.

It isn't pedantic to insist that 0 isn't a number, it is equivocal to do so. In most contexts it does not need to be treated like a special value. Temperature measured in degrees is an example where you don't need to treat 0 specially, at least not more than other values...