Yes, in some ways Ukraine is defending the West... proxy wars are nothing new, and this is definitely a proxy war by any definition of the term.

HOWEVER, if Ukraine didn't want to defend themselves and wished to preserve life, they would have rolled over, gotten rid of their president, and handed the country over to Putin by now. They've proven they are not above driving out their president and upper leadership by public demonstration, they have done it before specifically to get rid of a pro-Russian president and parliament prior to Putin's invasion of Crimea. They chose this path for themselves in 2014, they do not want to be involved in Putin's authoritarian state. It is up to us in the west to support that path and right to self determination.

It is also in the best interest of both to not get the west directly involved (yet, anyway), because Russia can and will take NATO troops being deployed as an invitation to start a broader hot war, and then everyone loses.

Both Ukraine and the west understand Russia doesn't stop there. Appeasement has never, ever worked with egotistical empire building dictators in the past before, and it will not work now. Just letting Russia have Ukraine would save lives, but inevitably cost more in the long run.