These counterexamples are comparatively straightforward because the input domain is well-defined and simply-structured, and a counterexample is trivial to verify. The same is not true for arbitrary vulnerabilities.
Computers are finite. Inputs are well defined and so is their structure (ignore for a second the fact that it’s all physics behind the scenes). Secure code is a conjecture. A counterexample for secure code processing bits is an exploit.
Also I find calling millennium problem solutions ‘straightforward’ baffling, to be polite.
