Borders are sacred, in that they are not to be violated with belligerence.

Gang wars do not prove the sacred nature of their turf. Governments are just gangs writ large. I doubt many want to see Russia win, but everyone loses the longer it drags on. Putin needs to answer for every civilian target struck, and his failed blitzkrieg definitely overstepped his proclamation as a "peacekeeper" in the disputed region.

The moment Putin used force to take that land, he jeopardized the hard earned lessons of the necessity of peace in the nuclear weapons age.

True, gangs with nukes require a measure of prudence. Unfortunately, the people who most desire power are also those with the least foresight on that topic. And the US is a nuclear power with a long history of sticking its nose where it does not belong, too, and meddling in foreign affairs with long-term tragic consequences.

If I value peace, and think those who support or at least apologize for this war discount it, why do I support a continuance of the war?

I weary of people proclaiming their anti-war bona fides only to make excuses for the current war, insisting this time it's different. The sooner Kiev and Moscow start talking peace, the better for all. The more the US pumps into the conflict, the longer it will take.

A fire doesn't stop burning because you ask it to. Neither will Russia.

No, but we are being robbed to pour gasoline on the fire.