Everyone ‘believes’ in gravity. And yet, we know virtually nothing about it. We don’t know how gravity waves (if there are any) are transmitted. We can’t block them (anti gravity boots!) and we can’t amplify them and we have no idea how fast they travel. There are very few people doing serious gravity research and development, either. But it’s apparently a law.
Evolution (and one’s confidence or lack of belief thereof), on the other hand, is enough to sway a school board election or get you nominated for federal office. I’ve never met an informed person who doubted the general facts about evolution unless they had an alternative view of the origin of species that they felt emotionally connected to. There are evolution skeptics who would prefer a different story, but no gravity skeptics, even though there’s a lot less science there.