I'd not say the recent far-right terrorism is just from some individual psychopaths with no value for human life. There's a ton of far-right/alt-right ideas out there, on platforms like 8chan, which actively demonizes certain groups of people. It's not like these shootings are just crazy people who just want to kill people at random; they want to kill the people they see as the "enemy".

Deplatforming 8chan isn't about limiting the ability of these people to kill large numbers (that would require effective gun control) - it's about removing a source of provocation, radicalisation, cheering, etc. for them both before and after.