Well, throwing out any option of modhood down the trash shoot, I actually concur with Iapetus that violence can never be considered justified 'just because'. I know that's not something US people like to hear, but that is how things work in Europe. No vigilante justice, no mob justice, only justice by law will stand.
The trade-off is that we have hate speech laws, and far stricter approaches to anything resembling neo-nazi rallies, and violence used by any individual regardless of their motivation. Punching people because you don't like them is something that cannot be avoided, but the potential medical costs resulting from it (and if brain damage does occur, this result can be a vast array of negative outcomes) are on the aggressor.
Even military police, despite having a state-granted sanction on applying a certain degree of violence, are held to standards of only using what is necessary. Europe isn't the US. If a cop fucks up by shooting somebody, that cop is going to jail until a court has sorted it out. That being a court independent of what the state wants, meaning states and their monopoly on violence are kept in check. This division of power is held to be solid in Europe, but only exist theoretically in the US, as the Trump presidency has increasingly demonstrated on all ends.
So yeah, when Iapetus is talking about a "ideological position", he's referring to privately held beliefs that do not directly violate the law or cause harm to others as understood in the EU. So he's not talking about this guy or some Charlottesville rally guy, as those people would find themselves being swept up by MP and in jail by the end of the day.
Because justice is a matter for laws that we've all agreed on, not some vigilante or mob.
I know that this sentiment gets lost in translation, but perhaps that is why you find yourselves where you are now to begin with. Instead of quoting Hannah Arendt and others on the existential philosophy and banality of evil, perhaps you should read them and how it effected actual policy and government.
I actually thought the same thing when the OP of this thread started with a Twitter account specifically targeting an individual. It may feel satisfying, but it's still targeted assault. Also, making potential martyrs out of people has literally never paid off. Imagine if his landing had been unfortunate, and how media reactions would have played out. If you want us to cheer for your narrowly avoided martyr caused by amateurs at politics...