Just because insulin is not released when you drink diet drinks doesn't mean something else isn't happening to stop weight loss (or increase weight GAIN if you aren't dieting).
I treat it like this - for stuff like diet drinks, where there is evidence that it MAY (MAY!) cause any complications in diabetes, i ristrick it, but don't REMOVE it.
Trying to find an excuse to keep doing something that you enjoy doing even when it MAY casue harm is foolish.
But, hey, it's up to you.
[EDIT: Diet Coke IS something that I get cravings for regularly. And I DO buckle to them and buy a 2L bottle which will usually only last me Friday night and most of Saturday. The fact that I guzzle it is enough to ensure that I DON't Have a constant supply of the stuff in the house!]