Yes, but there's also a flip side. Unfortunately, if everyone was moderate, there would be a lot less change. It's the extremists who bring certain issues to light. I don't think that they should have extremists running governments or other entities, rather, have a moderate run it with the extremists from both sides acting as advisors. That way, the issues get brought to light, but don't get out of hand. That being said, not every issue needs an extreme viewpoint. Some issues are fine with *only* moderatation.
The idea of a liberal government system is that there are lots of people who do have extreme points of view, but their agendas don't dominate everyone elses. There are few people who are moderate on every issue. Everyone has some extreme beliefs on one issue or another, but they kind of cancel eachother out and theoretically (and more or less practically) we end up on the moderate path. Where as with authoritarianism and communism one groups exteme agenda dominates everyone else's view.
One of the main tenents of the liberal approach, as Ursa pointed out, is that big change is slow. But that's generally good for big decision type of things. Nations need some continuity. We can't go around having a revolution every five years, because that's counter-productive. If something needs to change, it will get debated and moderated about 25 zillion times before its inacted - good or bad.