Because its an option that can be abused. It allows a user to post questionable material, leave it for a short time, and then remove it and deny they posted it. Yes, for 99% of the users here it won't be an isssue (of course), but on the occasion the ****** comes along it is just another thing for them to exploit.
Also, once a post is made, we never delete them. We try to keep all the content contributed to the site up permanently. On the board, old message containing useful info can easily be found using the search feature. So, we like to also keep the delete feature reserved for administration only to avoid content being unnecessarily removed from the site.
If you made a double post, you can always email that forums moderator and request for the duplicate to be deleted. If they don't catch it and do it any ways. I know I always toast a duplicate post when I run across them myself.
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Dan McClain, Editor
The Mustang Works Magazine
1991 Mustang GT - NOVI Supercharged 377 Stroker
1999 Ford Lightning SVT - 2000 Prototype updated by Roush