Plug-ins are created by people like you and me. Not by the WordPress Development Team.
Plug-ins get put in the Plugin Directory because they worked when submitted. As time passes, they may no longer work if they aren’t tested and possibly updated for each new version of WordPress.
I’m assuming you are talking about “Simple Post Thumbnails”. Its entry in the Plug-in Directory says:
Compatible up to: 2.8.4
Last Updated: 2009-9-17
Unless you are running Version 2.8.4 of WordPress, I wouldn’t expect it to work. Especially looking at “See what others are saying…” in the Plug-in Directory entry. Lots of “not working” type post titles listed. And at least one “no support” post.
A quick search by “post thumbnail” in the Plug-In Directory lists lots of choices. If I was looking for a plug-in, I’d start with Auto Post Thumbnail as it was updated a month ago, and supports Version 3.0.1 for WordPress. The only support post listed indicates it doesn’t support [gallery]
If you are upset by the delay in responding, please realize that “swear words” generally indicate a high probability of “verbal abuse” to the person who answers. The forum named “Plugins and Hacks” would also have been a better choice than here in “Installation” which is only generally frequented by volunteer “responders” who are good at doing a complete WordPress install.
Bottom line: plug-ins that don’t work with current versions of WordPress exist in significant numbers in the Plug-In Repository. Removing them would eliminate one hurt those running older versions of WordPress. Figuring out which ones to remove would also require a huge amount of time and effort. And is certainly beyond the resources of the current WordPress Project Team. There are, after all, 11,111 plug-ins in it, at last count.
