I mean the company is 20,000+ people and there hasn't been one story of anyone saying they were not allowed to get out of their NDA, nor any stories about being fired or treated poorly after being released. So either, no one took him up on the offer (highly unlikely given 20k people), or there was no issues when it happened.

It's also worth noting that it doesn't sound like what happens after you get released from the NDA was formalized. Given Bloomberg's reputation it's not unreasonable to think that asking for this puts a target on your back for later retaliation.