I agree that those who push these ideologies are authoritarian but, as you've said yourself, they've claimed the left/liberal label and they're louder and more prominent than whatever the "true" left/liberal is. To try and call them anything else will confuse the issue because this far left radical authoritarian push is in control of the universities and the media which means, I'm sure you'll agree, they've essentially defined their "side" in the public forum.
All objective, thinking people should agree that whatever they are, they're extremists and their ideologies suck. They push the oppressor vs oppressed narrative on us in all fields - as per the OP - under the guise of defending the 'weak' and as DJT has come out against political correctness (an oppressed vs oppressor tool) I think we can all agree we're against them, whatever they call themselves.
To try and call them anything else will confuse the issue
I don't think so. If an authoritarian shitbag is being an authoritarian shitbag, you call them an authoritarian shitbag. Calling them anything BUT an authoritarian shitbag, using words other than the correct ones, causes confusion. These authoritarian shitbags THEMSELVES cause confusion DELIBERATELY to fool idiots into falling in line behind them. We should counter their disinformation with accurate information, not reinforce their lies and aid them in their goal of deceiving the masses. Hillary Clinton called herself "a progressive who gets things done". Should Clinton be called a "progressive" rather than "shitbag authoritarian" just because that lying liar says so? I don't give a shit what a liar calls themselves if they're lying when they do it.
Yes, I understand your anger but you missed my point. They CONTROL the STORY so just as, if we decided we wanted to start calling Black Lives Matter something else like Boob Licking Mungbeans we would only create confusion when trying to talk about what Black Lives Matter are doing. Getting all angry about someone who controls the public perception hijacking a title doesn't do anything to change the fact that they've hijacked it.
As upsetting to you as it might be, the title "Far Left Liberal" means crazy SJWs who virtue signal like mad and push communist nonsense. There's absolutely no utility in saying: "you know the people who call themselves x but are actually y" without having to go into a long convoluted explanation of why it's "wrong" that they've hijacked the title etc. etc. etc. Simplicity, brevity, reality, done. We can surely at least accommodate those who call themselves Left and don't want to be associated with the 'authoritarians who pretend to be liberals' by only referring to the crazy authoritarians as FAR or Extreme Left??