This is exactly opposite of the truth of the matter.
If conservatives thought liberals were stupid, they wouldn't try to debate them. The problem with conservatives is that they give stupid liberals too much credit for being more intelligent than liberals actually are.
As for the liberals' claim that conservatives are evil, there are two ways to look at it. First, projection. Liberals are evil, and think everyone else is, too; and that conservatives are just lying hypocrites about moral absolutes. Liberals cannot imagine a life without the pretension of guilt-free sin. Liberals also think they know better than everyone else; and since they believe in moral relativity and "if it feels good, do it", they believe conservatives are evil for wanting to keep them from destroying themselves and others with soul-killing messes like teen sex, homesexuality, drugs and welfare dependency. On the other hand, all it takes for evil to triumph is for good men to do nothing. On this score, faux conservatives like the RINOs really ARE evil.
Very important point about “Projection” by the liberal, back FROM HIMSELF towards his opponent, and his opponent’s views or facts.
Ties with the “no moral clarity”.
“If “I” lie, cheat, steal, and hate, and “I” am a good person because “I” am a liberal with “good intentions” then “YOU” ALWAYS lie, cheat, steal and hate because YOU are a very bad person with evil, hate-filled, intolerant ideas who must be destroyed. Because “I” am a good person who wants to do good things that make me feel good. “
See how that feedback comes back as hatred?