That blockade of course was an agressive act against Cuba, and it was the correct course of action IMO because a rule that says that no country will be agressive towards any other country is unworkable because there is no power above the countries that could enforce the rule. (The UN is toothless.) If a country's leaders adhere to an unenforceable rule and insist on other countries doing the same, that will on average lead to more death and less prosperity for the world than if each country's leaders rationally pursues their country's interests IMO.
Some courses of action at the country level are more ethical than others, but it is more complicated than you imply it is and any ethical framework has to take into account certain realities.
Historically, this has never been true. Countless wars were started when the balance of power was threatened, even by such a small thing as marriage (can’t they marry “who they wish”?)
There's some set of [reason] the 'west' wants Ukraine to join NATO, and in theory, there's no issue with that right?.... but in reality, the consequences could be severe. It's silly to ignore the consequences when you've been informed upfront.
Most people wouldn't have any idea that it has anything to do with NATO, since the media is doing a wonderful job of misinforming. It's being pitched as 100% unprovoked aggression.
Oh wow, that's what I call thinking about the world as you wish the world were, rather than as the world actually is.
At the height of Soviet power, the USA were willing to fight enormous wars on the other side of the planet to stop a country voluntarily aligning with the USSR (dropping more bombs on it than all of WWII countries did combined, killing millions). They helped coups in countless countries and helped even genocidal regimes with the sole purpose of stopping USSR expansion, even when doing so was actually economically detrimental to themselves.
And the USA is far from alone in meddling with other countries' affairs. China, Russia, obviously, even not-so-big powers like Australia (ask New Guinea) and the UK (who loved doing that all over the world when it had the power to do so) will absolutely engage in whatever they can to make sure their interests are not compromised or even threatened.
