don't you think you help people navigating websites by making them more user-friendly ? I would believe that what you do doesn't really fulfill the definition of bullshit job as it helps people down the line.
A lot of it boils down to the Protestant Work Ethic having no place in the modern world. It made sense for situations where 'work' was physical labor. That benefits from perseverance and endurance. Mental work does not benefit from perseverance and endurance. It suffers tremendously from them. The brain simply does not work that way.
(One of the things that pisses me off in modern UI design on the frontend is designing resource-intensive pretty UIs. They look great on mockups. They work well on testing. Throw some actual, real-life data at them, and they slow your browser to a crawl. This directly limits the usefulness of a product.)