Does the functionality of blocking just a single user from an instance not exist with Mastodon?

This does bring up an important point however, in that the largest instances that will exist may not be the one that curates and manages the instance/ecosystem/users on the ecosystem as well or as reasonably, however creates a space (or bubble) of popular reaction - say being only "80%" compassionate vs. fully understanding. For example, what if a convicted rapist has done their prison time? I feel this would have very different responses based on the nation and culture and how much or how little actual rehabilitation and treatment people receive, if that society trusts the outcome of the system or not. I believe that keeping "unhealthy" people separate from "healthy" people will prevent them from learning - and of course has the potential to allow the unhealthy to learn further bad behaviours or reenforce ones they already have; this doesn't mean we should design for a free-for-all system like Twitter and Facebook are various degrees of. It comes down to compassion - which includes not dismissing or forgetting about people, even if they're not people we'd want as our friends or family.

In the case of a user who simply has a "trail" of accusations for unacceptable behaviour, do we foster "guilty until proven innocent" as an acceptable behaviour - blocking that user from society's online interactions - or should we foster more of a "innocent until proven guilty" - while perhaps keeping an eye on people who are accused of certain behaviour? If the a little girl accuses her brother of stealing the cookie from the cookie jar, however the boy claims it didn't happen - and there's no proof, it's not fair to me if to punish either child until there's proof: either the sister took the cookie and is lying, or the brother took the cookie and is lying; you could ban them from the kitchen with the cookie jar, though if they're ever left alone and there's no evidence like video to check back on, then either child could still take another cookie.

I then wonder though, if there become more trusted and larger instances that do put the effort (and cost) into curation and managing the community (the family of society), then smaller instances will and can tap into that network - however then not contributing or covering any of the cost. How does this imbalance balance out, or does it need to, even? Does it become a question as to whether people who want accountability are willing to pay a small amount to pay the costs of such moderation vs. people simply hoping someone else deals with it - a bystander effect?

I wonder if the Mastodon community or founder have any thoughts or beliefs to this? Likewise, what happens if you have a whole bunch of instances where people are in their bubble of communities, perhaps with less critical thinking time spent and more indoctrination, where then propaganda can easily be distributed without any potential to filter it out and protect the whole as easily; of course solid in-person, real-life community and connectedness is the only way to counter this, including developing deep trust with individuals who you trust are thoughtful and such.

I'm still not sold on that decentralized is the safest option, however it perhaps can help counter against bad actors who seek control of systems; in fact it could act as a canary if the powers that be attempt to make decentralized systems illegal - as part of an effort to control (and perhaps censor). However, so long as the community is educated as a whole, and is hyperaware of these characteristics and readies to counter it in full, to hold the line for peace and justice, then we're on the right path. In contrast to decentralization, if we look at Apple's ecosystem, trust and governance and good design, forethought, plays an important role in success - though everyone in that ecosystem is "paying their dues" via profit Apple receives. And contrasting that further to Facebook, whereby they profit off of the manipulative aspect of ads and with practically no vetting or oversight.