Chomsky has also stated that even if Russia was provoked by Ukraine/West, that doesn't justify his invasion and it's still an international crime that should be condemned by the left too.

Mate is arguing something similar, that Putin could have reduced energy supplies to the rest of Europe to put pressure on them to impliment the Minsk Accords...

Only Putin didn't reduce energy supplies to Europe first, Europe sanctioned Russian energy supplies and stopped paying for the oil! That's something very different, isn't it? Not only that Europe confiscated billions of Russian assets and billions investments and currencies in western financial instituions. Then the US destroys Nord Steam 2 pipeline.

Putin didn't want to stop oil and gas supplies to Europe for a number of sound reasons. First he didn't want to escalate the conflict in Ukraine to encompass all of Europe. He didn't want to employ the sanctions weapon first, precisely because it's so damaging.

If thousands of dead ethnic Russians in Donbass, some put the number as high as 12,000 killed over the last eight years, wasn't enough to force the Europeans to take action and demand that Ukraine stop the daily bombardments of civilian targets, then it's highly unlikely that imposing a cap on oil and gas exports to Europe would have achieved anything more substantial.

I don't think Russia had a realistic alternative to intervening in Ukraine. They knew NATO wasn't backing the regime and the military for nothing. The idea was to attack Donbass and Crimea when the time was right, when they were ready. Given Russia's history, waitng for the West to attack them, wasn't an option.