I know people on here will disagree with this, but I think many of these events indicate that online censorship is needed. I believe it's becoming increasingly clear that merely allowing far-right dialogue online is essentially responsible for ease of radicalization, and that proactive censorship would be the best approach to forestall this.
The shooter was self described as an eco-fascist and claimed his motivation were two events covered widely by the mainstream media. He was very clearly "of the internet", but are you convinced that deleting "far-right dialogue" would have stopped him?
What about the current state of journalism and politics, which was also very clearly something he aimed to exploit and seems to have manipulated at a far more effective level than past attacks?