Also depends on how you define terrorism. I mean, I would certainly consider lynching and other forms of extrajudicial homicide to be acts of domestic terrorism. I assume this is not a widely accepted view on the right, however.
I've always defined terrorism based on the connection between the objective of the violent act and the target(s) of said act. Terrorism is distinguished from other forms of violence is that the intent is to create "terror" (hence the name), not just to kill people you don't like. If the target of the attack is the "enemy" you want to cause harm to, then it's not terrorism. It's just a violent attack on someone you hate. If the target of the attack is somewhat random, with the intent to create fear of such random attacks as a means of influencing social or political actions taken by the people and/or their government, then it's terrorism.
Killing a bunch of (semi) random people in a nightclub, to send a message to the people/government that they should not be interfering in the actions of IS (or, specifically killing off leaders of said organization), is terrorism. That he also chose a group to attack that he had a personal hatred for is in addition to his intent to use the attack in a broader political way. Killing people who work at an abortion clinic because you consider them to be murderers, is not. Killing black people in a church because you hate black people, is not. Killing Jewish people because you hate Jewish people, is also not. What makes it terrorism is the intent to influence broader political or social actions by the population as a whole. The killing itself is not the objective, it's a means to the end of the objective. That's what makes it terrorism (IMO, of course).
I know that the term terrorism is often misused, but that doesn't mean that it should not have a specific meaning and use and we should attempt to restrict its use to cases where it's appropriate. If we use it just for the extra power it grants in terms of emotion/whatever, then it ceases to really have any meaning at all. And yeah, folks on all sides of our politics are guilty of this.
It certainly doesn't help that argument that the Administration repeatedly referred to the EO as a Muslim ban.
You have a quote for this, right? I know that their political opponents and the media often referred to it as a "muslim ban", but I'm not aware that Trump himself, nor anyone direct associated with him did. But I'm more than willing to be better informed on this if you have the information.