Because this is meant to stop a app that is freezing or locking up instead of having to reboot to fix issue, this isn't meant to keep the app off because every time the system access files related to that app it has to rub the app.... You can not stop any app completely.
Also, some of these apps that you "stopped" have a very nasty habit of restarting themselves.
http://community.vzw.com/t5/DROID-X-by-Motorola/DROID-X-Guide-Restart-Issues-amp-More/td-p/522082
JaySean wrote: http://community.vzw.com/t5/DROID-X-by-Motorola/DROID-X-Guide-Restart-Issues-amp-More/td-p/522082
I believe the OP was wanting to know about apps restarting after app os force closed in the task manager not about the device rebooting, this post doesnt really apply.
My post explains exactly why they start up back even after being killed by the Task Manager. But i apologise for posting a link. I should have just pointed out why.