"Russia is guilty", talk about stating the obvious. Whatever NATO has done in the past, it never justified what Russia has done to Ukraine.
I am personally not a lefty, those who've supported Russia in this brutal war tend to be leftys. But ethnic Ukrainians have a long and distinct history from Russians. They have fought for their independence for centuries. Despite the huge powerful states surrounding them, the Ukrainians managed to form several independent states over the centuries, one of the earliest was the Cossack Hetmenate, from the mid-1648 to 1764. At the beginning of the 20th century, you had the Ukrainian's People's Republic and there was also the West Ukrainian People's Republic. Moreover, there were other additional short lived independent Ukrainian states, so the struggle for independence by ethnic Ukrainians has a long history. So independent Ukrainian states did exist and ethnic Ukrainians definitely do exist and so does their rich heritage and ancestry.
They exist the same way that the Scottish, Irish, Welsh and Cornish exist. Just because the first 3 ethnic groups now have their own countries, doesn't mean that the Cornish don't exist, as the Cornish are their own distinct ethnic group with a well known history.
Back to Ukraine, the historical territories of where Ukrainians lived go beyond Ukraine's current borders. You have huge numbers of ethnic Ukrainians living in Russia in the regions that border Ukraine. The same applies to the countries that border the west of Ukraine. What you have to understand, is that there is a very long history of bad blood between Ukrainians and Russians. Yes, sure, both groups are closely related, but they are nonetheless distinct and the Russians have suppressed Ukrainians and Ukrainian independence for centuries. When Ukraine finally achieved a long lasting independence from the Soviet Union(Russia) in the early 90's, you can imagine how elated they were and how most of them are now of the opinion that every inch of Ukrainian sovereign territory must be taken back from Russian control.
You say that Crimea was taken from Russia, was the Donbass(Donetsk and Luhansk) also taken from Russia? I hasten to remind you, that there was a Ukrainian Independence Referendum in 1991, where the majority of every single Ukrainian Oblast(equivalent to our Counties), voted to be a part of the new independent Ukraine. That included Donetsk, Luhansk and Crimea. In fact, the overwhelming majority of people in each respective oblast of Ukraine voted for to be a part of independent Ukraine. So the people of Donetsk, Luhansk and Crimea voted to be a part of Ukraine instead of Russia.
This war is terrible and to see so many innocent women and kids killed by the Russians is dreadful. It is impacting every single person in Ukraine in a negative way. It is Russia who started this war and it is up to the Ukrainians to decide what to do going forward. But I can tell you that almost every Ukrainian I know, has said that they need to continue this war until the Russians are completely kicked out of their lands. The latest poll that was done, showed that 70% of Ukrainians want to fight until they defeat the Russians and regain their sovereign territory.
Talk about Russians who have lived in Ukraine being treated like 2nd class citizens is the worst joke I have ever heard. The Russian propaganda on this issue has clearly worked on too many people. Even when Russia first caused troubles in Ukraine back in 2014, Russians in Ukraine were not discriminated against at all. I have Russian friends in Ukraine who were enjoying their lives and were treated like any other Ukrainian. Russian was freely spoken all around the country. Russians had all the freedoms that ethnic Ukrainians had, despite Ukraine fighting a war in the east of Ukraine against Russian backed separatists and despite the fact that Crimea was taken from them by Russia.
Needless to say, since the brutal attack on all of Ukraine by Russia on February 24th, 2022, this ongoing war has clearly sewn animosity between many Ukrainians and Russians. However, the animosity seems to be mainly directed at the Russians who support Putin's regime. Many Russians who have lived in Ukraine for decades, support Ukraine in their fight against the aggressor in the East. If there is any ill feeling by Ukrainians towards Russians today, it is because of what Putin and those in the Kremlin started on the 24th of February 2022.