Sexism is an attitude or behavior favoring one sex over the other. While this is usually directed against women (misogyny) and can often be more problematic in that situation, sexism can just as well be directed against men.
Lars has occasionally been ironically sexist toward Alexis in order to troll her on the show. He does not actually hold sexist views. While Joe and Alexis haven't actively stated their views on this topic on an episode, they feel the same way.
On an early episode, Jackie Exoh discussed the ways in which sexism can be subtle and unrealized; she mentioned how some fans will be dishonest with her about her material, or will express surprise that she did a good job on a set, due to her being a woman.