Like, the US at least attempted to invent a casus belli for Iraq, and it was one that Saddam couldn't aggressively contest without revealing Iraq's weakness to Iran. Gaddafi was deposed because his administration killed protestors and provoked a civil war. Yemen is a proxy conflict against Iran and while our involvement is indefensible the goal of the aggressors isn't to annex the country.
Even Russia has benefited from this ambiguity: the international response to the Russian seizure of Crimea was very limited, and there was essentially no organized sanction over their campaign in Syria (which included at least one attack on US soldiers).
In this conflict, Putin's speech ahead of the invasion of Ukraine made it absolutely clear that there is nothing provoking this conflict beyond Russian imperialism. The erroneously published document outlining the rationale assuming a Russian victory confirmed those sentiments [1].
Ukrainian resistance bought time for a coordinated response and the personal heroism and charisma of Zelenskyy (along with strong American leadership in the background) galvanized Europe. A hard line against wars of conquest is a good one to draw and rally around, even if it isn't perfect.
[1]: https://www.businessinsider.com/russian-state-news-published...