As political landscapes change, the SPECIFICS that liberals and conservatives support also change.
A liberal at the time of the American Revolution would be classified as a right-wing extremist today. They were in favor of meager government because of their experiences with the English throne and Parliament. They supported the right to bear arms because they realized that tyranny can't withstand an armed populace. They supported religious freedom and feared governmental control of religion, not the other way around.
There is nothing wrong with being liberal, as being open-minded toward new and better ways of doing things. However, making hasty changes that might cause more harm than good just for the sake of change isn't being liberal... it is being reckless. We've seen socialism and the welfare state in action and it doesn't work. It doesn't take a genius to realize that, because of human nature, it will NEVER work. Humans are greedy and selfish, by nature, and so will not put forth effort without just reward. Humans, with some exceptions, will generally not expend any more effort than is justified by their needs and wants.
If you allow someone to not work and you still reward them, they will NEVER work. If you allow someone to expend less effort than someone else and get an equal compensation, they will continue to expend less effort. In reaction, the person expending more effort will expend less effort if he realizes that additional effort does not result in greater compensation.
The result is that in the end, either you change the model to allow compensation to be a function of skill and effort(this is capitalism) or you watch productivity fall to nothing. The other option is to force, by threat of imprisonment or violence, people to work for the compensation that the state wants to provide. They have now become slaves, in essence. This is what has happened in practically EVERY nation that tried to become a truly egalitarian socialist state.
So, I don't really consider liberalism as bad. I just think that most liberals don't really think independently, but yet, just as they consider conservatives to do, adhere to the same theories as those ideologically similar that came before them. Most liberalism today is a byproduct of socialist ideals that became nouveau grande during the 20's and 30's and had a revival during the 60's and 70's. Liberalism is driven by the desire to make things better... a desire innate to most people. However, if the call to action isn't tempered by consideration of the possible effects of such action, then it can cause chaos.
Passion is much like a sharp knife. In the controlled hands of a doctor, it can do wonders. However, in the hands of one that is reckless, it can cause mayhem.