okay. i'll bite. i'm gonna assume good faith, even though i wasn't afforded the same. it's a mix of practicality and the sort of culture i want to help foster on this website
bluntly put, it's not in this website's culture, and i do not want it to be. there already exist tools for setting boundaries. it's called silencing tags, and the block button, both features that you are encouraged to use liberally. there is no automated aggregation of any feeds, so curating your feed (and your general experience on cohost) is your own responsibility.
DNI lists make them everyone else's problem, which runs counter to this website's overall culture where we trust each other to moderate our own spaces accordingly. if there's some shit about me that upsets people, i am just going to trust that i am either already blocked by them, or they blocked the particular tags i post in.
the pragmatic bit. they don't work for their stated purpose. they do not establish boundaries effectively. no one reads that shit. no one who is scrolling the feed on their phones on the toilet at 5 in the morning is going to tap through someone's profile and be like "oh shit before i rebug something i better make sure there isn't going to be someone upset at me for having a pokemon shitpost for a profile picture" (not even making that one up. twitter was a hellscape. someone had a beef with someone else with a pokemon pfp, and went nuclear, and started to claim anyone with a pokemon pfp interacting with them was engaging in targeted harrassment. i don't even like pokemon, i just think a furret in jotaro's hat is funny).
it generally encourages antisocial and vindictive behavior, a thing i've seen first hand so many fucking times on three separate webbed sites, where someone got harrassed into leaving the site because they reblogged/retooted/retweeted a funny without running a pre-flight check list of inane fandom drama or proshipper/antishipper purity culture bullshit. i do not want that shit to happen on this website, and while i'm not stupid enough to think that correlation = causation, i do not want that shit in my spaces.