Many adults routinely vote in deeply immoral ways. For example, they vote in favor of taxes to fund government schools. Or they vote for politicians whom they know will tax their neighbors.
These are clear, unambiguous violations of the Golden Rule (“Do unto others as you would have them do unto you.”)
Would these unethical voters want you to encourage an armed thief to break into their homes or bank accounts to steal their money? Obviously not, yet they are sanctimoniously delighted to encourage armed thieves who call themselves “IRS agents” or “sheriffs” to break into their neighbors’ bank accounts and steal their money.
And when one of their neighbors resists, they are quite pleased when this “tax evader” is kidnapped by heavily armed thugs and locked in a cage. Whenever they have the pleasure to be a member of the jury that will decide whether a “tax evader” is guilty of a so-called “crime” and should spend years being raped in a cage, they happily shout “Guilty, guilty, guilty!”
Not all people do such wicked things, but many do. And those who do such things are clearly showing, by their actions, that they do not think the Golden Rule is a correct moral rule. They are showing that they live by primitive, childish rules such as “Might makes right” and “Whatever ends I selfishly desire justify whatever means that I (or my rulers) can use to achieve them.”
If you know such a person then it is appropriate for you to apply his own moral rules in all your dealings with him.
For example, if you selfishly want his money and you have the means to take it away from him, you are not bound by any moral rule to refrain from doing so. You would simply be doing unto him what he has already encouraged others (e.g., his rulers) to do unto you.