This is because a bunch of us use the Fediverse (Mastodon, etc.) as a general purpose social media network and really don't care to have the entire timeline be doom and gloom about how bad the world currently is, but want to read the other things folks have to say. So a bit of etiquette has built up over the years to stash those things under a CW (think of it like a subject line) so you can read it when and if you have the spoons to do so, and can happily ignore it and wait for something else from that person, say, cat pictures, without having to unfollow them.
In a more elegant world, Mastodon/Fediverse would have the concept of topics, and I'd be able to follow `@mh+cats@example.com` without following @mh+uspol@example.com`, but we're not in that elegant world. Mastodon (nor Pleroma, nor Pixelfed, nor any of the other Fediverse software) doesn't offer anything like that, short of multiple accounts, which comes with other big problems.
Ok, that's actually very cool. And I deeply share this sentiment:
> don't care to have the entire timeline be doom and gloom about how bad the world currently is
..
> In a more elegant world [..] the concept of topics, and I'd be able to follow [..]
One can dream. I used to regard the idea of filter bubbles as a negative thing, but I'd be perfectly content with being able to craft my own right about now.
