Once you post in the forum that thread/material/posts become property of the forum so we cannot give permission to delete the threads to all as it could be misused .
If you want this thread to be closed/deleted, make a request by giving reasons and pointing to the inappropriate posts and we will delete if deemed proper to do so.
You can delete your post by yourself (within stipulated time) by pressing edit button of your post and deleting the contents therein.
But to delete a thread, you have to follow the procedure, as stated by ST da in previous post.