it would be entirely reasonable to wipe it to eliminate any possibility of using it to access work materials illegally.
MAYBE. But their former employee is still under the obligation to deliver all their company security credentials and information; passwords, etc, in their brain or in their possession, required for their operation to continue after the employee is released. And acting to destroy any of the above would clearly be malicious justifying charges against their former employee.
Also MAYBE. But there are a lot of otherwise "entirely reasonable" courses of action which are Illegal.
I mean if you don't have as much $$$ as you want, then it's "perfectly reasonable" to go take somebody else's $$$, But that's why this country has Laws.... and that's defined to be Theft, and it's strongly discouraged.
The burden on not accessing work materials illegally is on the former employee; that doesn't permit them to destroy work data or work computers' operating system installs in doing so.