I wonder why this question about the possibility of zero bugs was closed as "not constructive"
Since it's very much on topic for the field of software engineering, and it's not an opinionated/flamebait sort of question, I can only think of one close reason: that it will solicit debate and extended discussion.
But this question is the stuff software engineering is made of, right? An answer is possible, and you can quote software engineering books and papers. Right? You can mention practical matters such as the cost of finding bugs, diminishing ROI, etc, or theoretical aspects such as the feasibility of formal proof in the general case, and all of that with proper references.
It doesn't seem so open-ended it must be closed.
edit: as Yannis points out, I misread the close reason, which is actually "not a real question". I still think it is on-topic and can be salvaged into a more focused question.