Human level programmers generally suck too. Unending security holes have been human behavior ever since we started sharing computers.

Also, programming isn't a destination, it is a process and everyone has a different ruleset on what that process looks like. Writing a computer program of any complexity is not a determinalistic process. Trying to compare it to a detemanilisic tool will just leave you with broken analogies and a poorer understanding of the world.

Or another way to say this. If programming were deteminalistic we'd have solved it without AI.