You read a passage talking about groups of people who provably commit real violence and advocate for more of it, establish "autonomous zones" in cities as part of protest actions, attempt en masse to impede physically the lawful actions of legitimate federal LEO, and explicitly promote agendas that include the destruction of fundamental state institutions; and you imagine that this will be applied to establishment candidates with good chances of winning in a democratic process. This appears to be based on nothing more than your personal impression of the POTUS. I find that to be completely and utterly unreasonable.

Benjamin Song should be all the evidence you need to illustrate that the phrase "domestic terrorism" is completely appropriate to describe things that are actually happening. But there is so, so much more of it.