there are fascists in Ukraine, like in a lot of countries

Most countries don't have a fascist government that violently suppresses the left. Israel and Ukraine are about the only ones (and maybe Modi's India to an extent?) right now.

It's not about a "right" to invade. The point is this was the only option left with a coup gov that doesn't care about prior peace agreements, kills people for resisting (like Eastern Ukrainians in DPR & LPR and Crimeans), and is being blocked by the US and UK from negotiating.