They absolutely use liberal as a pejorative, but since it has other meanings to it as well, it’s not strictly defined as solely a pejorative

But the Wikipedia for liberalism (https://en.wikipedia.org/wiki/Liberalism) does in fact have a blurb for it:

"Consequently, the ideas of individualism and laissez-faire economics previously associated with classical liberalism are key components of modern American conservatism and movement conservatism, and became the basis for the emerging school of modern American libertarian thought. In this American context, liberal is often used as a pejorative.

There are tons of other words that can be considered as a pejorative, from “weird” to “moron” to “Tree-hugger” to even “Nazi”