These aren't really "leftists" (generally) - who've seen/saw McCarthyism in action, and naturally reject this kind of bull$hit... These are DNCIA Democrats, who're the NeoLiberal half, of the NeoCon Uniparty in DC and London and Brussels, etc.. They're Globalist Imperialists. Sometimes they ape the language of the left, other times they'll ape the language of the right. The only thing they really care about is control and power in this world. If Russia is an hour obstacle to their plans, then they target them - whether Orthodox Christian, Muslim, or protestant. If Iran, Syria or Palestine (or Venezuela or North Korea) are a bump in the road to their goals (Global Monopolar Hegemonic Empire, and Technocratic Totalitarianism - for all) then their goal is to flatten them - religions or sects or indigenous political trends, be damned.
Any Politician who isn't 100% on board with their Cheney-esque Endless Wars for Empire, and who speaks up, even in the smallest ways for peace, and just International Relations...Will be targeted. Trump spoke out (quite sensibly) against going to war against Russia...even for improving our relationships with them (which Obama and $hillary and Nuland had deliberately sabotaged from 2008 onwards - following the plans adopted during the Cheney/W. Regime, things like the Orange Revolution in Ukraine, and the one in Georgia, eventually ending in a declaration that they should both join NATO), while he was campaigning in 2015/2016... THAT was what began the active Bipartisan Campaign against him. $hillary and her people were HANDED the Steele Dossier contacts - from the RNC.
I'm a leftist. Jimmy Dore is a leftist, I suppose that Glenn Greewald and Matt Taibbi and Michael Tracy could be described that way, too... We're all certainly to the ACTUAL left of Rachel Maddcow and the rest of the MOCKINGBIRDs at MSDNCIA. None of us fell for this Neo-McCarthyite BS. I don't think any of us qualify as Trump supporters, per se...but our differences with him are legitimate and rooted in real political questions - not about some made-up nonsense about him being Russia's "Manchurian Candidate". So our disagreements aren't this kind of TDS related crap.
Notice what happened when Trump tried to improve relations with North Korea... The Beltway didn't know what to do about that... Except to declare that they were against it, immediately. And then, they just sat back while Pompeo and Bolton queered the deal - sabotaging it in ways both big & small.