I am sure all kinds of illiberal people would describe themselves as liberal. As Oscar Wilde said of hypocrisy, it's a kind of homage paid to virtue.

The point is, it is best used as a general term across the political spectrum, like moderate, or pragmatic, or even kind. You can have a liberal conservative or a liberal socialist, or a liberal anarchist for that matter. They aren't going to agree on much, but they are at least committed to behaving towards each other in a civilised manner.