If you write anything (be it nice or nasty) and you blog it, it is out there. Deleting something that has been reblogged doesn’t really make sense and is highly annoying (I’ve been guilty of this myself, shame on me!). Once reblogged the post lives on via someone else’s blog and if they have good tumblr reblogging etiquette, it has your name attached to it.
I think the best policy is: if you say it, leave it be. Write an apology if you need to or edit it with the infamous “UPDATE” clarification. But removing it is just not kosher.
