I agree with this, and, as a result, I don't believe there is any possible approach which results in 0 people assassinating political figures for what other people say. I think the same conclusion can even be reached if people were supposed to be expected to be perfectly rational beings.

I do believe education on how to effectively engage against an idea which feels threatening is better equipped to handle this apparent fact than bigstrat2003's approach of teaching people to not say certain beliefs because they'd be worth killing about. That doesn't mean it results in a perfect world though. Some may perhaps even agree with both approaches at the same time, but I think the implication from teaching the silencing of certain beliefs from being said for fear they are worth assassinating over if believed true ends up driving the very problem it sets out against. Especially once you add in malicious actors (internal or external).