Blocking people leads to them searching for ways around your block really quickly. Making them waste time not realizing they have been blocked, such as endless retries or shadow bans, is much more effective at making them stop bothering you for a while longer. Time spent doing this is time they can't spend being malicious on your platform.
It's unfortunate when a non-malicious user gets caught in one of these traps...
"its easier to just punish everybody than single out the person actually deserving of punishment" is actually a common defense of collective punishment
the equal and opposite response would be, "Sounds like you never had to actually deal with such a usability problem yourself", but I'm not interested in trying to devolve this discussion into one about you and me, instead of the topic
Can't access your mail archive going back a decade - could be a huge problem for some people
Sure, it's not as bad as getting sent to the gulag. But the problem with most of these tech companies is far bigger than not being able to post a meme.
I do believe you're misapplying Blackstone's Formulation. I think it's perfectly fine to presume guilt in some cases when operating a public service. This can be reformulated as making users go through extra steps designed to screen bad actors. We in fact do this at places like airports (and increasingly schools) all the time.
For instance if your user happens to be an unwitting botnet member (or even if he has a newly assigned IP previously belonging to one) - his IP will be suspicious and you can "punish" him accordingly. Also Blackstone's ratio was 1/10, not 1/1000.
Blocking people leads to them searching for ways around your block really quickly. Making them waste time not realizing they have been blocked, such as endless retries or shadow bans, is much more effective at making them stop bothering you for a while longer. Time spent doing this is time they can't spend being malicious on your platform.
It's unfortunate when a non-malicious user gets caught in one of these traps...