Yes interesting that "conservative" is not a slur at all. No conservative denys being a conservative. The left seeking an equivalent "slur" has to apend something to the word.. like "arch conservative" as you point out. But the new one is of course "neo-conservative" or better yet for them "neo-con" That one pushes the movement to the the fringe and suggests there was something wrong with conservative that they had to come up with "neo" ..
But that is all marginal carping from the left. Conservative stands tall and proud. Liberals have to defend themselves against the uneasy sense we get that they will pull something off truely goofy unless we watch them very very closely
Liberal's attempt at negative labeling is to call conservatives "Right Wingers".
They can't understand why it doesn't irritate us.
The problem for liberals is, no matter what label is applied, it is just a word to categorize something. They may (and often do) call all conservatives "Mean Assholes". If being called a "Mean Asshole" puts you in a category of person who believes:
1.) Personal responsibility is a necessity of participatory citizenship
2.) Government has its purposes, but should be minimized
3.) The military is an honorable, and vital profession
4.) National Defense is not just a campaign issue
5.) Peace in and of itself is not victory, the end all, or the be all
6.) Not everyone is equal in capability, both physically and intellectually
7.) Not everyone is going to make the same amout of money, or deserves to
8.) The Judiciary is meant to interpret law, not make it.
9.) Discrimination does not become something else because you call it something else.
10.) Words have meaning, and cannot be endlessly twisted to suit your needs.
11.) Morality may not be completely absolute, but it is closer to being absolute than relative.
Then yes, conservatives will square their shoulders and say "Yep. I am a 'Mean Asshole'..."
Liberals do not understand that a label is only as good as the person or group creating the label. Basically we all know it as the admonition of "Consider the Source" when insulted.
Like Ronald Reagan, most conservatives are comfortable enough in our political "skin" to enunciate in precise terms what it is that we believe in.
Liberals, progressives, socialists, communists or whatever other label they may apply to themselves, cannot do that. Their dogmas and ideologies often require that people NOT know and understand what they are up to. I think Richard Nixon said it best when he spoke of Alger Hiss:
"If the American people understood the real character of Alger Hiss, they would boil him in oil."
The descriptive titles Liberals, Leftists, Progressives, Socialists or Communists may be substituted for "Alger Hiss" and retain complete accuracy.