You have experience with previous threads of yours being bombed, and there are several occurrences that have taken place in this thread already. List out rules restricting such things from occurring again, and yes, you even have to put down the simplest of rules (ie: No mythical/supernatural beings permitted). Some people just don't get it on their own, but that doesn't mean it's right to put the blame solely upon them.
I can understand it is time consuming -- trust me, I know -- and frustrating to do all that just so you can enjoy a solid roleplay experience, but without it you will just be destined for disappointment on a daily basis.