That is an actual question. I can’t promise you an answer.
There is an exception. Robert Evans from Behind the Bastards and Cool Zone Media does at times mention PathFinder, so he has at least somewhat deviated from the norm, but others choose to mod their D&D rather than play something else. I have a feeling that his tastes are wider than this, but also I have a feeling that PathFinder does scratch an itch for him, because he does seem like the kind of guy who would be interested in tactical combat.
Otherwise, off the top of my head, these include Spice8Rack, Sarah Z, Carlos Maza, Zoe Bee and Thought Slime. Each a great content creator with varying degrees leftist ideas (or at least varying on how they express their ideas). Yet, with the exception of Thought Slime, I’ve seen them expressing their love or like of D&D on their various platforms.
This is weird to me on two levels.
First, if you are a leftist, why would you choose or prefer the most corporate roleplaying game of them all? Yes, they have great licensing regarding their rules systme, but they have been trying to mess with that recently, even though that licensing kept the game afloat for a very long time, but what do you expect from a corporation that went out of their way to find the most evil CEO possible (if you read into the employment history of Cynthia Williams, it’s almost as if she was a caricature of an evil corporate management)? HASBRO fired over a thousand people just before last Christmas just to show their stockholders that they were willing to do just that. Shouldn’t leftists be boycotting actions like this?
Second, there exists a huge number of independent and great designers and publishers, who have similar or better licensing, nevermind the systems themselves being so, so much better in so many ways. These systems are more streamlined, serve their purpose much better, leave a lot more room for creativity and don’t have the baggage of 50-or-so years of expectations.
One would assume leftists would be very much into the culture around games like Apocalypse World. How many other games has that spawned? They might not call themselves leftist, but that is a very leftist approach to intellectual property: you just let others use it. Not because you want them to market your product, but because you want to see what others come up with those ideas. When WotC tried to change their licensing, so many of these people came out to pledge that they will never do that.
It’s so sad that the cultural zeitgeist is still strongly behind D&D. The world could be doing so much better on this. We don’t need the corporate overlords. I understand there is no ethical consumption under capitalism, but there are still shades here. You can support a disgustingly badly managed corporation that has sold out completely or you can support someone who is just trying to get by with their cute little game. Sure, buying that game still means you are giving some of that money to some probably problematic platform and there are multitudes of other problems, but you are still choosing a lesser evil. That is not optimal, but these are still lesser evils that you can actually get behind. This is pure evil versus a little bit of negative consequences.
I would hope creators (like the ones I mentioned) would find something different. It would serve them, their audiences and these independent creators better. You know, do a leftism.