The article blames both. I think the focus on DMCA makes sense from the point of view of preventing this from happening again. HackerRank likely will exercise more caution, given the PR and monetary cost of this episode, but the DMCA still exists and is prime for abuse by others.
A large part of the world certainly feels like not having guns widely and easily available can help.
Keeping in line with your analogy, I mean.
No part of the world wont file murder charges to the guy pulling though.