Youre literally saying the same thing as me.

All negative numbers have the most significant bit set and 0 is the number with no bits set, ergo 0 must be positive since the most significant bit is not set.

Now arithmatically, this is untrue. We'll usually treat 0 as neither positive nor negative (or in certain cases both negative and positive) but bitwise, In terms of twos-complement implementation, Zero is positive. We know that since it exists in the unsigned version of the types as well.

Hopefully you'll see that some day.