Because it looks like the person is using it to drum up publicity, possibly in an attempt to get Apple to pay them a decent settlement to get the media to shut up. I’m not really a fan of people using the legal system in this way.
What should be the exact dollar amount to avoid "looking like he's using it to drum up publicity"? You presumably have some idea of what the "right answer" is since your gut is telling you $1bn is too much.
If I was mistreated by the police for a few days with no permanent harm, arrester on insufficient evidence, the police should pay me a few hundred or thousand dollar a day, maybe. Apple should pay nothing because because they did nothing wrong by sending evidence to the police.
The real problem is that the government considers arrest without conviction to be a civil duty, not a tort.