I think it's difficult to lay blame anywhere in particular.
From having read many many opinions about the deal, it seems very likely that Ned really didn't fully disclose what exactly was being sold, nor the details of previous agreements from back when Dan Larimer was still largely driving the project.
At the same time, someone as allegedly shrewd and aggressive as Justin Sun would be expected to exercise "due diligence" before entering a deal... and it seems like he didn't. Either that, or he did know precisely what he was getting into, and simply didn't care," which is the root of what offended many Steemians.
I'm not sure what happened with Dan Larimer or Ned Scott or Justin Sun, but the move to create HIVE was not the way to address this issue. The digital assets on the blockchain should not be used as leverage for the internal disputes and promises broken which were based on verbal agreements. This group is acting on there own, on behalf of millions of accounts. If they believe HIVE could be better than Steem, they should have started the blockchain from scratch. They have instead copied the intellectual property of millions of people for their own gain. Do you remember the Google Brain lawsuit when they wanted to copy all the books from public libraries? It did not finish well for them. This move by HIVE will fall under that legal precedent.