I don't think there is.

This happens all the time--recently, a podcast app was removed from the Play Store because it could be used to listen to content which didn't meet Play Store guidelines. The only way to fix it is to post about it and generate enough outrage that Google hears about it and can undo the ban.

yes. husky in particular is a fork of another app called tusky, that internally implemented a login blacklist of explicitly-nazi instances and instances with lolicon content, after the author decided they didn't want those users running their software. husky's explicit sole purpose is to be tusky without that blacklist. tusky has not been removed from the play store.

i'm not familiar with the other apps on the list but i expect it might be some issue like promoting such instances in their registration screen.

also interestingly, the instance OP links to qoto.org is known within the fediverse for being full of creepers, because they've implemented a partial defederation and block circumvention. if you have an account on qoto.org, you can follow users who've blocked you, on instances that have blocked you, because it will recognize such, pull a list of posts via RSS instead of via activitypub, and fake an activitypub actor internally to generate posts for your feed. in their defense they have said that the posts are public anyway, and the user could just browse the public feed with a web browser, but it's clearly a bit different when posts from a person who has tried to block you appear in your feed normally as an item you can interact with. it's certainly against the spirit of consent.

8 years ago "Reddit Is Fun" was removed from the Play Store because it included "sexually explicit" material and it was related to the inclusion of NSFW and hate subreddits in the app's default subreddit list. Google was fine with people adding that stuff on their own, they just didn't want the app to be promoting or pushing it. The app was adjusted and updated and it was reinstated.

https://old.reddit.com/r/Android/comments/r3dhg/reddit_is_fu...

So the issue isn't so much that content is accessible, it's when the content is more integrated with the app.

Big 4chan apps like Clover got banned off the play store long ago. The reason given was nsfw content, but in the app you had to manually add nsfw boards, much like Reddit's nsfw communities. Picking and choosing which social media platforms to ban has already been a thing.

The thing that isn't being mentioned is that Google allow apps that make "reasonable" attempts to block content that violates their anti-hate speech policy. Reddit has shown that they're willing to ban the very worst content. No idea about 4chan.

In the case of the Fediverse apps they can't block anything because firstly there's no resources to police it, and secondly it's kind of the whole point of federation to let the user see what they want without getting in the way.