The law of gravity doesn't say "you shouldn't do x", it just is.
If you want to go against it...well you can't.
And while you can give a false prophecy by doing math wrong, you cannot go against it. If you put 1+1 balls in a box, you will have 2 balls in that box. You cannot end up with 3 or 1.
I don't see anything similar with morality, you can do stuff that is considered "immoral".
This is what I mean by universal:
Math is universal (independent of time and space and independent of person using this particular concept). Examples:
If someone says ''2+2=-5'' is wrong, then this statement is true:
- independent of time; this statement was true 1000 years ago, is true now and will be true in a million years from now
- independent of space; this statement is true in North America, in Portugal and even on Mars
- independent of person; this statement is true when you say it, when I say it and even when the pope says it
Imagine someone claiming ''2+2=-5 is false unless it serves a public good; then 2+2=-5 is true''. Idiocy, right? Or something like this ''Upward buoyant force that is exerted on a body immersed in a fluid, whether fully or partially submerged, is equal to the weight of the fluid that the body displaces, except for Chuck Norris who cannot be immersed, because he has lawful authority to walk on the water''.
Morality is also universal (independent of time and space and independent of person using this particular concept). Examples:
If someone says ''it is wrong to initiate violence, e.g. to rape), then this statement is true:
- independent of time; this statement was true 1000 years ago, is true now and will be true in a million years from now
- independent of space; this statement is true in North America, in Portugal and even on Mars
- independent of person; this statement is true when you say it, when I say it and even when the pope says it
Now imagine someone claiming ''gang-raping Birdy's child is wrong, but if it serves a public good then it's okay'' - would you agree to such an exception from the rule?
Ethics (and abstractions like state laws and regulations and religious laws and regulations derived from ethics)
are not universal (they are always creating exceptions from the rule). Examples:
- stealing is wrong unless ... (exception follows: majority agrees to it, etc.) - real life example: ''A person commits theft,
if without lawful authority, such person knowingly: 1 controls property of another with intent to deprive him of such property ...'' Arizona Revised Statuses, § 13-1802
- raping is wrong unless (exception follows: a person wearing FBI jacket is permitted to do so) - real life example: ''A person commits molestation of a child,
if without lawful authority, by intentionally or knowingly engaging in or causing a person to engage in sexual contact with a child under fifteen years of age'' Arizona Revised Statuses, § 13-1410
This is your ethics at work! I do not want such a world for myself and for my children.