No precedent is being set here. Sanctions aren't new, and their purpose is to put pressure on the citizens to change their government. It's already been done to the US before as well. Eg. The Gulf states raised US oil prices to protest America supporting Israel, and Canada recently targetted products from key states for tarrifs in response to Trump's. Russian misinformation bots are the same thing, punishing the citizens to make the government more compliant.

America is a democracy, so influencing the citizens is effective. Cooler heads still need to prevail - you can't use all your non-war tools, or you'll only be left with going to war