It is far less of double standard than what you think. The key question is the legitimacy and mandate of the government. Western governments can claim legitimacy and mandate through democratic process (even if it is not perfect), which forms a social contract for their citizens to follow their laws. But if government is tyrannical and does not enjoy legitimacy then it's very different situation
I've never understood how that legitimacy extends to foreign policy though, especially the "coercive" kind.
Like, democratic elections obviously give the elected legitimacy to govern the populace that just elected them. But sanctions (or military interventions or wars) by their very definition are enacted on a different population, that had no democratic means to influence that decision.
UN sanctions are at least somewhat different because they are supposed to be decided by vote of the constituent countries.
But US sanctions are essentially "some people elected the President because they liked his views on domestic tax policy or trans people, therefore he gains the right to call airstrikes on some place halfway across the world or forbid the entire world from doing business with that place".
