Ukraine
Because they (supporters of the war) don’t think in terms of moral outrage but in terms of geopolitics. They see it as pushing back against primarily the US and to a lesser extent the UK. In a sense they feel they were “forced“ to invade. I’m not talking about your average Russian but more like the upper caste, although the view Is probably not that uncommon with the average man on the street who pays attention. As KiwiSaint attested with the taxi driver. And it’s more common in the older generation.
And yes, if 250k Russians have to die to accomplish the vague goals set out by Putin, it’s a cost they’re willing to pay. From their perspective, mostly people who dont contribute much to the Russian economy anywaym which is mostly petroleum and raw materials export and some agriculture. You don’t need a lot of people for that, and the subset you need can be protected.
It is a very old school mentality. Not necessarily Nazism, but more like 19th-early 20th century nationalism and balance of power politics. Not all that different than how many European and even Americans thought during that time.
Imagine if most Americans held these same views or beliefs about the legitimacy or the moral/ethical reasons for bombing North Vietnamese cities, towns, villages, dams, no calls from left-wing, British/French philosophers like Bertrand Russell, or Jean-Paul Sartre in bringing America before War Crimes tribunals for war crimes atrocities, unjustified mass killings, bombing against civilians, using herbicides that poison water, ground, trees, forests and crops like Agent Orange? I suppose most Russians wouldn't have batted an eye meanwhile, the rest of the civilized world CALLS US murderers, savages, and despotic imperialists for military or political decisions in Vietnam, Cambodia, Grenada, South Africa, or the Middle East.
It took us nearly a decade for to have 58,000+ soldiers dead and wounded in Vietnam, we never suffered 1/3th of those casualties fighting in both Iraq and Afghanistan over two decades and in the case of Vietnam, most Americans were screaming bloody murder to withdraw most or all US combat troops after NVA's Tet Offensive in January 1968.
In terms of public opinion reacting to late 19th/early 20th century European balance of power/pre-WWII European nationalism reacting soberly or subtly not being too enraged by their involvement in foreign wars, to a point, you're right, but certain wars(like the Second Anglo-Boer War from 1899-1902, Russia in the Crimean War, even the American Civil War) had severe, nasty blowback in terms of vicious parts of public opinion opposing the wars themselves, Pres. Lincoln likely wouldn't gotten re-elected in 1864 if Sherman, Grant hadn't captured Atlanta, most of Georgia, militarily splitting the Confederacy in half. For the first couple of years after Boer War started, most of public opinion in Europe was against British involvement, large percentages of British public opposed the Boer War, many leading Liberal/Labour, even Tory politicians openly rooted for the Boers almost like they wanted their own nation to lose. Lincoln even wrote in his personal diary in August 1864 that his re-election defeat looked "increasingly likely" because from that particular point in time, Northern victory looked uncertain, and Lincoln's Democratic opponent, George McClellan, swore that if he were elected, he'd call for an immediate end to the Civil War.
And UK mightve lost the Boer War if they hadn't decided to get nasty, take off the gloves, and stop pretending South Africa was a "gentlemen's war", Lord Kitchener mandated a policy of burning white Afrikaner farms and settlements, forcibly uproot hundreds of thousands of white, black, and Indian South Africans in internment camps under strict, military supervision where disease, malnutrition, hunger, abuse and neglect, ANF sometimes physical and psychological beatings, sexual assaults and rape.