Your claim: "stop calling far-left groups 'left-leaning.'"
Ight man. Let's break this down:
3. Antifa -- The mission of this group is embedded right in its name. It opposes fascism, which believe it or not, still exists today in the form of jackbooted vigilantes like Kyle Rittenhouse and groups that are self-styled protectors of the realm (but in reality, protectors of Donald Trump personally) like the Oath Keepers and Proud Boys.
Antifa is a response to the organization of right-wingers who arm themselves to the teeth and haven't denounced violence. Antifa is highly decentralized. There's no one leader and no one organization.
Antifa doesn't rule out violence and has been condemned by Democrats and Joe Biden because of it (quite unlike Donald Trump boosting the Proud Boys). However, antifa deploys other tactics such as online activism and doxxing, etc. Antifa is one of the main reasons we haven't seen more events like Charlottesville, because many of the white nationalist participants were exposed to their landlords and employers and suffered real-world consequences.
Was Donald Trump on the case? No, lol. He called them "very fine people." And the federal government has been awfully slow to recognize white supremacist groups as terrorist groups overall. So, citizens organized and took it upon themselves to repel these white nationalists. It's a democracy's immune system kicking in.
Are there communists and far-lefties and anarchists in antifa's ranks too? Yes, no doubt. But they're disconnected from any political group that holds actual power, unlike white supremacists' pipeline straight to the top of the federal government, not to mention white supremacists' sympathizers in police departments and such.
Here's an expose on the Oath Keepers for you to chew on.
https://www.theatlantic.com/magazine/archive/2020/11/right-wing-militias-civil-war/616473/
Why do antifa folks mask up? Well: because they're smart. They don't want to be doxxed, harassed, and possibly assassinated by their counterparts on the right.
Like BLM, the notion Antifa is bankrolled by Soros would be worth another laugh if it weren't just another regurgitation of age-old anti-Semitic tropes straight out of the Protocols of the Elders of Zion.
Conclusion: Okay, you get this one. We can consider antifa to be "far-left." But you're missing the point of a far-left group organized in opposition to far-right groups that deploy violence and deploy violence much more often.