This means it doesn't matter if Canada, Mexico, Cuba or any other country near our border voted to have an alliance with Russia. We would NEVER allow them to have military offenses next to our border. We invaded Cuba multiple times and brought the world to the edge of nuclear war over enforcing this Doctrine.

Online discussion gravitates toward trying to provide the other sides hypocrisy: "if you like apples, you like fruit, so if you you don't like oranges, then you're a hypocrite," and the like. The problem is that apples are not oranges, and in this case very many people opposing the invasion of Ukraine opposed US interventionalism as well.

This is definitely an apples and oranges situation. Ukraine joining NATO isn't the USSR putting missiles in Cuba. This isn't the cold war. Russia not in a nuclear arms race with a real expectation that first strike capability is necessary for the survival of its nation and people. There's no reasonable view that NATO was going to use arms in Ukraine for an invasion of Russia, rather than for defense from, well, exactly this.

Further, now most people agree that most Cold War intervention by both Russia and the US was both bad morally and strategically, so making an analogy that other people have done this, so therefore we shouldn't oppose Russia doing this, doesn't make sense. It's like saying "no one opposed the US war in Vietnam, therefore no one should oppose Russia invading Ukraine." Lots of people opposed it at the time, and basically everyone agrees it was a terrible war now.

Never mind the fact we committed actual war crimes by torturing people without trial at Guabtanamo Bay and waged dozena of recent wars in the name of profiteering and influence.

Yes, this is bad, too! It should be stopped like the invasion should be stopped. "Everyone should do bad things in foreign affairs because otherwise it's hypocrisy" is not a good view of the world.