Right now, my head is full with exams coming up this week and I don't have all the patience I'd like to do a small dissertation on this matter. I'm just leaving a quick comment (edit: nvm, it's the small dissertation after all) here to avoid, as is usual, to find the thread locked, when I return here to post — probably next weekend, which is plenty of time for this to evolve into what most will label “drama thread”.
From what I understood, it seemed you were concerned less about the erasing of the post in privilege of the lack of a notice, then moving on to suggesting users should be notified when one of their posts get deleted.
It stroke me as odd, because it seemed you wanted to know why, then you said people just should get a notice. Which raises the question: why would there be such a dire need for a notification if not for the user to know the reasons? Is it possible that this user is just concerned not in his particular case but that the site might lose its members because of people getting distressed over their posts being shadowy sickled? Is he on a humanitarian mission?
Then you said users needed to know why their posts were deleted but you don't seem to care why yours was. I am a little confused, but I am not being sarcastic.
I understand and underline that it does «piss users off». One of my recent experiences was the deleting of a large post justifying the creation of the Medal of Honor, in an attempt to prevent, once more, someone from defiling one of my ideas into some twisted aberration.
However, the act was reversed, and I believe you should post in Admin Contact whenever you feel some decision wasn't right. There are still a few staff members (including administrators, unfortunately) who believe the... so-called "Code of Conduct" to be a tome of rigid doctrine more than what it should be: guidelines to be interpreted and applied case-by-case. Where one moderator was too severe, another could have been more soft (note in next paragraph).
Users complain not only about posts but also about resources — which makes it all harder because, since we have so few moderators for each section, there is a sort of absolutism in the criteria to approve a resource (which is that of the section's respective moderators). Relating to the above paragraph, I tried to maintain an environment on the reports forum where moderators should give input on what to do concerning every situation.
Yellow (0 rep) warnings was an idea I toyed with and eventually began using and they seem to be taken quite more lightly.
That said, I also understand why most moderators are not open to disclosure why they have deleted a post. Sometimes, the user will be looking for the reasons merely to discredit them and attempt to bend the rules. Understand that, when negative reputation is given for rule infractions (which we already do), not all users will be happy about it.
When one user provokes another who in return responds with flaming, both of them should receive negative reputation, the first for being provocative, the second for flaming. I found myself neg-repping the second harder than the first, but I can't count how many times that was interpreted as supporting the wrong side («WTF HE BULLIED ME AND I GET -7 HE GETS -3 LOLZ», «So John Flamer insulted the other guy and you gave Grumpy more neg-rep?»). Users inclusively get the notion that it's something personal against them. Right on top of my head I have two examples: FlamePhoenix, who sent me a ragePM and left the site, utterly convinced I held a grudge on him and stalked him, and HeroSlayer, whose nickname I remember from nowhere, who supported my demotion claiming I was a bad moderator in the thread Ralle created to announce it (furthermore, neg repping users was inclusively mentioned as one of the reasons in support of my demotion).
To cut it short on that topic (and others), I will not elaborate on my experiences, but I said this to mention because (being a new member, you probably don't know) staff-user relation has always been a fragile topic around here. Most users on the staff are new, but they know some of our history. Secondly, answering the «why»s is very noble, but not always as pacific and straightforward a resolve as it might seem at first. Nevertheless, I hope the recent fiasco of mass bans and censoring taught people a lesson, especially those now in the staff.
On my end, I would suggest to make users able to see deletion notices, but I believe this was by default and then they no longer could. That story surpassed me. Alternatively, just use the Visitor Message or yellow/grey reputation.
P.S. — Okay, this turned out MUCH longer than I thought, I'm rereading a bit and I think I abstracted a bit, I shouldn't be posting this at this time. I hope you take something out of it. Sleepy, logging off.