If the original poster asks for removal it should be..Or at least closed.This is a public forum and we all post freely.For some reason if the OP feels he made an error in his post or has changed his mind it is his Post.
It isn't owned by the rest of us.We are just responding to his post.
Why is it so important to you that the threads not be removed?
The Op should give good reason to the mods,admins for the removal and if it adequate then it should be done.