I think that's the difference with Ukraine. Zelensky's done an excellent job in presenting Ukraine as a democratic, European-leaning nation based on western values. Of course this is inaccurate, with Ukraine beset by the same corruption as most former Russian held countries, but the West can see themselves in the Ukraine Zelensky has presented, and when we see European women and children killed, injured and fleeing, with their men standing their ground alongside their charismatic, democratically elected leader, against a brutal invader, everyone in the West wants to help. These aren't Afghans, Syrians, Rohingya, Uyghurs, Kurds or other peoples in the developing world needing help from oppressions... this is Europe, Europeans that look like us, that we directly identify with, in need of help. There's a lot of unfairness in what I write above, but it's how I best explain the West's enthusiasm to help.