Modern Liberalism is based in large part on the idea that being rich does not make the air cleaner. There are limits on the value of personal wealth and there is little difference once you cross the threshold into extreme levels of personal comfort.
The Right holds dear the idea that rich people can take care of them selves and the goal should be to maximize personal wealth.
Taken to an extreme each of these ideas break down, but IMO the left wing is closer to reality. Granted in the real world we need huge helpings of corruption, stupidity, and hypocrisy, but that's going to infect any form of government over time.
Then there are all the lies such as the republican leadership hating the idea of ever banning abortion etc. And all the liberal "think of the children" reteric that sounds great but is a pointless power grab.
I agree with you that in general the Right and the Left are philosophic ideals. Philosophic ideals which taken to their ultimate end in practice could be disastrous.
But I've always looked at liberalism as more of a practical economic not philosophical approach to problems.
And yes economics always ends up deep inside both politics and philosophy but deep underneath all of that ideological baggage there's still a kernel of practicality.
This kernel of practicality aims for the most efficient use of resources.
To achieve that goal, there are many real world practical strategies:
1. Rule of law - free of both government and private coercion. (No cartels like the RIAA, OPEC, DeBeers, but also no labor unions or government cartels like what used to ma bell AT&T)
2. Free competition.
3. Free information. (Not to be confused with perfect information in perfect markets).
The above imply that active fraud and monopolistic practices are against the law.
But I, like many other libertarians would take it even further.
By that I mean that in practice there are many things for which the free market does nothing. Health is one example.
The demand for insulin is the econ 101 example of things for which normal supply and demand doesn't work.
So for me liberalism is not a fanatical extreme of no government ever, but a practical optimization. Seeking the most effective market and government which implies a very small government but acknowledges that things like market failures exist and some government is essential.
That government is preferably small, local and a direct democracy like Switzerland.
They hate anything which wrestles control away from their philosophy.
And so they use any crazy/authoritarian/doomed/etc scheme as a straw man to attack liberalism/libertarianism.
Because in their minds, only their control of society will lead to peace and prosperity. Any loosening of their control must lead to doom.
Therefore if it's a disaster it MUST be because it veered off from their philosophy.
But the irony is that both far and left and far right are untied by their desire to control society.
And that's why they can never attack the control elements. They can never blame the disaster on them, they WANT something like that.
They use the failure to attack everything else and just call it an obscure word for too much freedom!