It is always sad to see a member going, disappointed from this site !
I can though, understand both sides here:
The "I will delete any futher forum discussion on deletions" way of speaking has a very sour taste for me. It sounds to me like Big Dictator Speaking" and this does not really fit in nowadays times in my opinion.
On the same time, I understand the moderators that they do not want to have neverending discussions on deletions on the forum, or even worse, to see the forum becoming a place, full of complaints and rants.
There must be a way, to deal with this in a more diplomatic way ? I personally would have thought, that letting everyone say what they have to say in public, if it is obvious that there is not more to add, it would be a gesture to say "if all is said, and no more relevant information to add, I would like to close and delete the topic". This would give everyone a last chance to add something to the case and the topic closed in a proper way. I understand the need for such topics to be deleted, because everyone does start an own topic and there is a chance, that the forum gets cluttered with these rants.
I hope, there is a chance to avoid members leaving in anger from here.