I think if they helped organize and promote storming the Capitol they should be listed as terrorists.
As far as your average hate group, I’m very torn. Terrorist is supposed to be someone acting against the government or against the citizenry that uses coercion or violence to interrupt or inhibit political goals of the country. Something like that. Terrorism is a political act not just people who don’t like other people, not just people exercising their right to free speech. I do think hate and hate speech does sometimes rise to the level of terrorism though.
I worry about the slippery slope of quelling free speech so much that it leads to government having the power to quiet anyone in disagreement with the government, whoever the government might be at the time. Remember how Trump wanted to shut up some news organizations? What if the laws were working for him to do such a thing.
I do think we can identify hate and violence meant to destroy our democratic process though. Or, when hate is systematically trying to take away or destroy an American citizen or group their equal rights or especially their right to be safe and to live.
If a group targets a black church, synagogue, or mosque, to me they are terrorists too, because that is an assault on the country, not just the groups named.
So, I tend to be on the side of listing the KKK, Proud Boys, and other NeoNazi groups as terrorist organizations.