Is it possible Ukraine isn’t entirely innocent? Sure we assume they are from our point of view, but that’s the nature of propaganda, how do you really know what is reality?
Also, there's nothing Ukraine could have done that would have made Russia's actions justified.
Finally, when you follow the Russian statements for a while, you notice that they are self-contradictory. This lets you disregard their arguments as pure lies - the truth is not self-contradictory.