You live in a fantasy world.You only need one. Do unto others as you would have them do unto you.I challenge you to come up with a list of objective standards. You might think prohibiting murder would be one example but every culture defines murder differently. Even our own culture doesn't agree on what is murder and what is not in every case.
You are still confusing man's subjectivity for the standard being subjective. That just isn't the case. It can be solved through inspection.
If someone is trying to kill me what is the standard? I don't want him to kill me so your standard says I shouldn't kill him. Where does that leave me?