I know you're not arguing that it is, you're more talking about public opinion. I think you're probably right. But I wish that weren't the reality.
I can't imagine what you mean by "perfect rule of law", but I do know it isn't the antithesis of authoritarianism. The opposite of strict obedience to authority is no obedience to authority -- meaning no hierarchy -- or anarchy.
My point is, we're judging how authoritarian a dictator is based on how benevolent they are. While a dictator is capable of ruling.. "equitably", the fact is you still have a dictator who could change his mind tomorrow. So it's not that we're mad about having a dictator, we're just mad this dictator is being a bigger ass hole than yesterday.
So the first continuum I proposed is actually one half of the continuum between anarchy and authoritarianism.
As you point out, even if it's true for most of us, most of the time, it's the edge cases (abuses) that matter most.
There was never a mass consensus in the USSR that it was authoritarian, because it was not permitted.
When I say not permitted, I do not mean that they had people with guns going "THINK THIS!", but that social pressure and group-think were utilised to ensure that nobody broke ranks - just like media control in the US and UK ensures.
It's very easy to rule people by pitting them against one another, and putting them in a state of fear, envy or suspicion of their fellow cit.
Perhaps things are authoritarian when a wide range of people expect abuse from the people in power, whether or not they recognize it as such.
Or, maybe it's more sinister than that, and we only truly recognize authoritarianism in retrospect.
Bingo, you get it. Put a frog in a pan of cold water, bring it to the boil. It'll stay there, perfectly content, until it cooks.