The entire community benefited from this knowledge, so why punish the DAO?
Because that's what they signed up for. It was clearly stated in the terms and it was built on top a very new and untested platform.
Additionally, how will justice ever be served, or are we saying this is un-necessary in the blockchain world? We're not there yet.
And we'll never get there. It's impossible. We can't write bug free code, and there will always be people to take advantage of the mistakes we make. Serving justice this way is fine with me. The problem is, in this case, only a small minority had interest in getting justice, yet they managed to pull enough political influence to see it through. Had it been my $5 stolen, I would have never seen justice.
A system where justice is dependent on political influence already exists, so there's simply no need for a new one.