Iris accepts delete events from the current user and the deleted event's author. But it could potentially blur or delete posts that have been deleted by enough people that you follow.
Discussion
And of course the threshold can be set by user, or the feature disabled
As long as it is optional I like it for the people who can’t live without it, to each their own. Downvoting on Reddit and mass flagging campaigns on social networks have shown (imho) that flagging sadly does not work because what ends up getting flagged is different opinions first, actually bad content last.