Your point is moot because it doesn’t demonstrate censorship, because you can easily make an account that isn’t blocked.
so I could no longer access these instances
Incorrect; you could still access those instances, seeing and reading posts; you weren’t able to post or comment to them yourself, and crucially are able to do so if you make a new instance that was federated with it.
my ability to access content got censored without my say
Okay, so you just don’t know what “getting censored” means. This isn’t how this word is used. You don’t say “my ability to read books at the library was censored”, you say “they censored library books so I have less ability to read them”.
When you block an instance, you are censoring users from accessing it
No. That’s not what censoring means, for one thing, and for another, you can still access the instance, just not participate in it.