I believe humans are vastly more stupid than you give them credit for.
It's the HN effect. The pool of geniuses here suggests to the reader that the pool of intelligence outside of this microcosm is similar. It's not.
Criminals are overwhelmingly stupid. It's why LEO catches so many of them. Smart people don't tend to do crime, they tend to sell their skills to more legitimate enterprises.
By leaving the reason vague an attacker has no immediate feedback and no clue how to remedy.
I vastly prefer the way this works now.