I understand, but doesn't a wiped drive create reasonable doubt? Maybe there isn't even the need for a special law about this, just use reasonable doubt. I also have the feeling that there already are laws/case law about what to do in case of illegally destroyed (potential) evidence, we just don't know about it because we're not lawyers.

It does and it was. The defendant appealed, they figured out what was on the drive independently, and the evidence was weighed against him. This article is catnip for amplifying reasonable anti-authoritarianism into a general distrust of laws and justice.