I think it is fair to also consider the excessive centralized moderation like the kind we criticize on reddit to be a part of the user experience. Those similar problems that only affect specific instances, but not all, is a part of the user experience here with lemmy.
To be fair, email works the same way and there are a number of domains that different email server admins block to avoid spam or for any reason they choose. I know some smaller ones block gmail and others because the gigantic amount of spam they send. I also recall the relatively quaint days of Ukraine drama in 2014 had motivated a local university to block my email because my web/email host was located in Ukraine.
Sure, there are times when individual server admins will muck things up, but rarely does my email not make it to where I want it to go. My point is that I think that this is being made into a bigger issue than it is.
happens with email servers all the time