Whoever deleted it hard deleted it, meaning it was an administrator.
A soft delete is something moderators and super moderators do. That's when you delete a thread but have to specify a reason, and the deleted thread is still able to be browsed by admins/mods to see the offense(s).
A hard delete, on the other hand, is something only administrators can do, and no reason needs to be given as to why it was pulled. Also, no trace of said thread is left.
The reason being is so that admins (who are higher up in rank) can see what decisions mods make and decide whether or not we're doing our jobs. Whereas admins answer to nobody, so they're free to what what they want.
Long story short : An admin nuked your thread, bro.