Advocating genocide is not violence. You can have someone on the internet yelling to kill all the muslims but if they never actually throw a punch, they are not committing violence.
There is also a very real normalization that goes with online threats. If 100 people talk about running over liberals in a chat room, and then one of them does it; the other 99 facilitated that violence.
Groups that do just that have governmental support in Canada, the UK and many other first world countries, and this is one of those things that one simply isn't allowed to speak of publicly.
We need to be able to attack bad ideas, and few ideas are worse than "Death to all people of <ethnic group>!"
I'm generally for free speech, but very much against governmental support of groups advocating violence and very, very against shutting down discussion of whether, for example, the Muslim Brotherhood does or does not advocate ethnic violence.
Verbal violence is a real thing that has real impact on people. Ask anybody who was in an abusive relationship, even if they were not physically beaten. Or consider that Trump has not physically thrown a punch, but most reasonable people would agree he has caused a lot of harm to minorities and immigrants’ safety and ability to share their brilliance with the world.
We don't take into account peer-pressure when charging adolescents. However, that does not mean that peer-pressure does not exist, on the contrary, it is sometimes the sole motivator behind the deed. These things don't conflict.
If Bob only made the decision to punch Alice because Mallory asked him to, yes Mallory shares in the responsibility. But that implies a notion between Mallory and Bob that is rather different from mere advocation. I do not consider a scenario in which one party convinces another, both with agency, to be advocation. In some cases, I would even consider the person who provided the imperative for violence to be more responsible than the person executing the imperative.
But we are getting into Wittgensteinian weeds here with respect to definitions. For my part, I consider advocation to be the scenario in which one person or group receives peacefully submitted recommendations for a course of action. I think an advocate can be responsible, but I do not think it is productive to use one word to describe the impact of both advocation and execution of a thing.
Using your real world example, I can agree that Donald Trump has committed real harm to various people. I cannot agree that Donald Trump’s position is one of advocation; in fact, I would say that Trump is one who is advocated to. A position of advocation, in my opinion, implies a position that is lesser in power to one which has the power to effect the change on their own.