I'm sure they could, but they don't want things removed from threads to prevent it from affecting the flow of the thread.
Nor do they want to be inundated with people asking for every little thing to be changed or removed.
The site owner is the only person that makes money from the site, all the mods/admins are volunteers. As it is they keep pretty busy, so adding one more thing for the volunteers to do would be a bit much.