If the appearance of some social media is "there is reasonable discussion but as soon as something shows up that's awful, discussion stops there, but it remains up for all to see" - that's going to have difficulty brining in new people.

Instance blocking but still giving the appearance of condoning the content is going to lead to what appears to be toxic spaces to everyone who hasn't taken the time to carefully cultivate their block lists.

Ignoring and personally blocking users and instances means that admins and moderators won't have as good of a view of the health of the communities when everything ends with a troll comment that no one but new users see.