The invasion doesn't help. There are more Nazis in Ukraine than ever. But if Ukraine is demilitarised, the Nazis would then also be demilitarised. The point isn't really to legitimise the invasion on anti-nazi grounds, it's just to push back against the western narrative that the Nazis are few and hold no power in Ukraine. There isn't one Nazi political party, there are several, and Nazis have a lot of power in the Ukrainian military. Russia is only invading because they are scared of NATO on their border, not to help Ukrainians.