Hi Soubriquet, hi all,
Thanks for rapping our knuckles asking about this.
First off, we'll hold our hands up and say you're right - it looks as though we have used the standard, "This thread has been deleted at the OP's request. (We don't normally delete whole threads but we will do so when it is to protect a poster's privacy.)" message rather a lot lately. And we completely take your point, the second sentence is stretching it a bit.
Here's what our Talk Guidelines say about thread deletions:
"We don't generally delete whole threads; it's frustrating for those who've taken the time to write responses to see them removed. That said, we're here to make people's lives easier, so if you have a pressing reason for wanting a thread you started to be deleted, please report it to us and we'll take a look."
We're not always able to go into details about why we've deleted a particular thread, but suffice to say, we don't ever do it lightly, especially when a lot of people have invested time and energy in posting. We always try to explore other options first - be that a retrospective name change, moving the thread to our 30-days only topic, torching the place, whatever.
At the end of the day, we're generally a pretty fair bunch. We may not always get it right, and we're truly sorry to anyone who feels unfairly treated in the past when they've asked/begged 
for a thread to be deleted. We haven't changed our policy as such, but there's a slim possibility we're mellowing with age.
We'll do our best in future to always post as comprehensive a deletion message as we're able to, so we're not trotting out the standard message, and hope to win back a bit of trust.
Oh, and MistressMerryWeather, if you want us to take that old thread down for you, just say the word. No one will notice after all this time... 