Why would you not be welcome? Is it for your political opinions? Even if it were, I don’t think they would personally shun you unless it entails attacking minorities.
That aside, and having said that of course it is everyone’s perrogative to judge this behavior, I personally feel it is an exaggeration. Not every instance is about free speech nor should they be, at the end of the day the fediverse is about creating communities, one is able and should shape them into what their vision of that is. This is not authoritarianism, in this case they said it is due to their inability to moderate.
Even if it weren’t for that, it is good that communities don’t federate with every instance, aa I said, not everyone is about free speech and changing opinions some are here to have a good time and for that adequate protection is necessary.
I myself prefer deciding myself when to block other instances, so I joined one that let’s users decide. But if other instances decided to block us I would understand and either move on or join another instance to interact with them without thinking much about it (having multiple accounts is kind of easy on the apps,)
I think I’m kind of used from servers blocking one another from my time on mastodon and I’ve seen the necessity of the practice, for example an anime focused group blocking bot instances, brigading, alt right groups, etc.