If you're anonymous they have no reason not to kill you as a punishment and a warning to future whistleblowers (same as mafia rules).

If you are anonymous, how they would know that it was you? Also, they will have much more important task of damage control, when punishment of somebody will be only a proof and additional attention to the information.

Mafia killed snitches, who informed police or agreed to testify in court, not made some information public. Here you have same situation, really. BigBusiness, just like mafia, account such wistleblower hiding data from public as a snitch, who is ready to witness to police or testify in court or something like.

There is difference between "People should know that it is Big Boss who racketing our town, here is proofs" and "I will give police/judge proofs about who is racketeering our town". Especially in the case of corrupt law system, when there is zero probablility that BigBoss/BigBusiness will be really punished. In the best case BigBoss/BigBusiness will be fined, nothing more, but people around will not be warned about source of danger, because "private person protection" and all that stuff.

It's always a David against Goliath scenario and I applaud their bravery and self-sacrifice

I will applaud their bravery only if that bravery have real results, specifically in releasing meaningful information about participants. With exact names, locations, documents, bank accounts, sums and all that stuff. Released to public without any redactions, not to some fucking court or lawyers who will sweep this stuff under the carpet and that's all.