I just had a thought. In the history of the U.S., I think that all good societal reforms came from the liberal train of thought at the time. Let me make a list and tell me if I'm wrong or if any additions are needed.
Abolition, Emancipation, Civil Rights, Women's Suffrage, Desegregation, Franklin Roosevelt's 'New Deal', Social Security, etc... There are probably alot more, but I cannot think of one conservative reform movement that was a) succesful or b) good (I have prohibition in mind). But if it is the case that it is liberals who have this seemingly apparent trend in beneficial reform movements, then why are the movements of today (gay rights, end to capital punishment, supporting the separation of church and state) so vehemently attacked by conservatives? Is it because it breaks their tradition for the sake of others? I would venture to say so.
History shows that societal reform movements (say, civil rights) are aimed at breaking the status quo (say, segregation) for the relief of a group(say, minorities). How is that any different from today with modern movements (say, gay rights) which is aimed at the status quo (say, restricting those rights) for the relief of a group (say, the gay/lesbian population). The only difference I see is a change in setting, identity, and different rights in question.
The one thing that should be mentioned is that conservatives are not entirely wrong. It is important at certain times and under certain circumstances that we keep the status quo and hold to tradition. (i.e. imediately after 9/11 and the wave of patriotism) but at the same time that ideal of keeping to tradition should be kept in check (i.e. now with the near civil war in Iraq). These are just some thoughts though...
[Edit: I just realized that I started something with my last post and didn;t follow through, my bad]
1. Liberals care more for the will of the minority over the will of the majority.
2. Liberals care more for animal and foreign rights than that of human beings and their fellow citizens.
3. Liberals are 'communists' because they desire total government control over peoples' welfare and the economy. At the least, they are socialists at heart who detest the concept of capitalism, and being rewarded for success.
4. Liberals encourage failure in life, rewarding the unproductive and punishing the productive, and blaming the failure of the poor on the success of the rich.
5. Liberals are Godless, because, by and large, many of the policies they support contradict Biblical philisophy (gay marriage, abortion, removal of references to God or Christ from the classroom/government/public property).
6. Liberals weaken our country by de-emphasizing the importance of the military in defending our freedom.
Ok now that we have a conservatives definition, we can try to see the link to insult. In this list, I see a trend of fear. This is a fear for the protection of the current state of things and to disrupt the current state of things is to disrput the general welfare in this mind-set.
So I think it is safe to say that once someone who pertains to the dictionary definition of a liberal comes in contact with someone rooted in tradition, namely a conservative, the conflict arises in the feeling that tradition/the status quo is immutable.
Once this threat to tradition arises, some of the more base conservatives will throw out names and insults that they attach to the term liberal. These insults will ultimately degrade the name of that which they are directed to. Now since America has a slight conservative majority, it would make sense that those who have influence over the conservative community might lower themsleves to name calling and thus have a negative affect on the community and their perception of liberals.
Any other ideas out there guys?