What I don't get is what is stopping people from joining a smaller instance more adjusted to their tastes? Like if you join large instance made for the general user, don't be surprised if you see a political opinion or meme you disagree with. world and ml tend to block only the most egregious of instances.
There are plenty of instances that cater to the political and social leanings of people if you really can't stand being outside a bubble, but fediverse isn't simply one site, and you can't bully or complain your way into shaping the culture of lemmy or fediverse in general. That is part of the beauty of this site, and for how many here complained about the homogeneity of reddit, its funny how now the big complaint is people are seeing opinions they don't like.
There are simple solutions to all of that, but it involves being proactive in the users and communities you block, and being selective of the instance(s) you join.