The definition of a terrorist reads as follows:
"a person who uses unlawful violence and intimidation, especially against civilians, in the pursuit of political aims."
Antifa as an organization that perfectly fits this description. Showing their true colors over the past year in the wake of Donald Trump's election as the "black block" they have trashed cities, assaulted men and women of all ethnicities and have shown a willingness to kill in the name of being "anti-facist" (as shown in the GOP baseball shooting). These people are violent and are a danger to Western society.
As someone has pointed out the definition of terrorism aligns with how antifa is acting. They are creating violence in the pursuit of their own political agendas. Someone needs to show them that the violence they bring will not be tolerated.
The attacks are going to continue to escalate until more people end up seriously injured or worse.
ANTIFA has, at least since February, been continuously and unrelentingly committing acts intending to silence opposing beliefs and attack others. If they were individuals committing the acts, however, and ANTIFA disavowed them, then ANTIFA would simply be a left-winged organization with a history of violence. Instead, they wholly and actively support the terrorism their members commit and plan to commit in the future. Since the organization itself supports and commits acts of terror, they are a terrorist organization.
The difference between them and the far/alt-right, or even BLM, is that the far/alt-right groups disavowed the individual who committed the act of terror and did not condone it. When a member of their organization commits or plans to commit an act of terror, the organization disavows and disassociates with them. The same is true for the Dallas shooter and the Black Lives Matter movement. Therefore, the far/alt right and BLM both have had individuals commit acts of terror and have had a history of violence, but they themselves don't condone and even discourage and disavow terrorism, thus making them not terrorists.
On the flip side, if BLM or the far/alt right ever did condone or plan terror attacks, and they were approved of by the organization as a whole, that organization would then fall under the category of a domestic terror organization.
Look back at the early days of fascism on the internet, groups such as the EDL had huge followings as did groups such as EXPOSE, they both used the same tactics to try and get each other banned/arrested therefore, if fascists are going to be treated as terrorists, so should ANTIFAS.
An organization that believes breaking windows and attacking those with opposing views is an effective way of making change is a terrorist organization. They are willing to create anarchy in order to get what that want and they have no respect for anyone around them or the country they live in.
These thugs show up with the sole purpose of starting violence. They have grown lately and they may even be getting paid by the left to incite violence which the biased media then blames on the other side. They are terrorizing people in the streets of America. Stop them now!
Terrorism is basically politically charged violence, and Antifa fits that description. I don't think they are a serious threat, after all their numbers are smaller than FOX News would like you to believe. Conservatives know that white supremacists are in their camp, so they try to find the equivalent on the Democratic side. The thing is, statistics show that left wing violence isn't even close to as dangerous and deadly as right wing violence.
ANTIFA folk respect differences between individuals, and wish to celebrate that fact whether you're gay, trans, black, or even if you're a straight white person. Look at Charlottesville. No facists died that day - but an ANTIFA person did. And who killed them? A facist. They are not violent people unless it comes down to protecting those who are marginalized or otherwise let down by society. Facists on the other hand will attack regardless of whether they've been provoked - purely based on the colour of someone's skin, who that person loves or even due to a disability which is out of their control.
They are as far from terrorists as you can get. I would argue the opposite for facists/white supremacists/the alt-right or whatever you want to call them.