Removing Posts/Threads

I would like to ask why players cannot remove their own posts or threads at any time. I can understand not being able to remove others, but why not just our own? or any post on our own thread. it would make it easier and keep spam, innappropriate, or unwanted things out of the thread, like even things that dont even remotely go with the actual thread itself. Hell, you can even make us give a reason to why we are deleting the post/thread if you really want to know why we want the posts/threads gone.