He chooses not to use it on privacy grounds. But, this is a common problem with most national identity databases tbh. Its more likely a political decision than a privacy one.
Not just for privacy, but broken processes and duplicitous technological claims. It doesn't solve the problems that people assume it does. It does solve other problems, which is why there's so much enthusiasm for enforcing it.
But it's hard getting mainstream attention for how these are different sets of problems.
Isn't social security number in many countries widely used, especially where it matters (insurance, banking, pension, etc.?). So we have a better solution? There are some privacy preserving IDs (self sovereign IDs), but I think to get such services, you still need a central ID?