It’s a cute idea but in practice, very, very few users want to deal with content moderation. The far majority of users just want to consume good, moderated content without worrying about removing bad content. Getting people to volunteer as mods is already hard enough. Making it democratic will not help I think.
Also, mob rule is not always the best. It is not uncommon for totally reasonable takes to be down voted - sometimes just because it started getting down voted and then others went on the bandwagon.
The way to achieve democracy in communities is not by making moderation democratic, but to make community switching easy. So if you don’t like your community mods, you can easily go elsewhere. That is also a kind of democracy I would say.
Maybe a middle ground could be moderator elections. At least then it’s a representative democracy and it would largely work as it already did. But again, very few people volunteer as mod so I believe you’ll find that the mods you could vote for would be very, very few mods (potentially just 1).