I have largely come around to just fully disliking Harris without any hesitations, and I definitely think that one of the big elements of that (even though I could not have articulated before now, so thank you H.) is this position on "humans as rational actors". It's not even really a debate. We are totally, completely NOT rational actors at all. Even if you JUST zero in on humanity's pervasive, nigh inescapable "optimism delusion", it becomes clear how hilariously non-rational we are in just simple day-to-life, even among people are who are proportionately aware of this delusion.
And this is without even really dipping your toes into the maelstrom of cognitive biases and waaaaaay headier content you see routinely on Three Pound Brain, for examples. Even philosophers/scientists/thinkers who are relatively of clued-in to the Bakker-esque material are mostly incapable of making that last big "leap" and wrapping their heads around the full scope of human delusion, especially when it comes to grappling with the "language" involved with investigation of non-intentional-anything.
TBF, I do RSB trends toward a more "radical" outlook/perception of other somewhat like-minded "thinkers" (dunno what else to call these dudes anymore) and can be overly dismissive of folks who are basically treading the same waters he is, particularly when it comes to "intentionalist talk" (though again RSB is not off-point here exactly, he just laser-focuses in on it with seemingly anyone whose actually throwing their hat into the ring).
Then again I may just have no fucking clue what RSB is talking about and I'm totally wrong. I flip-flop everytime I dive into that blog.
sorta TL;DR
I haven't really stayed up on Harris since my early-to-mid twenties and am still catching up on Peterson, but my opinion ATM is that Harris is a well-spoken, well-educated individual with some incredibly shallow views on a number of alarming topics and, ultimately, is just kind of an asshat. Peterson is similar, but IMO suffers most from an inability to articulate himself on a handful of interrelated and relevant topics/issues which then COULD be used to cumulatively build up to a coherent intellectual vision. These factors, for each individual, lend themselves to popularity and to the sense H. describes of "tending to agree with most of what Harris/Peterson says, yet still something doesn't sit right." This is because (most, certainly not all) of their views are fairly straightforward and non-crazy, and in piece-meal do make sense, but there's little cohesion (especially with Peterson) that make all these little pieces build up into some digestible, coherent, visionary concept.
TBF, I have less against Peterson than Harris. Harris's warmongering and views on religion, especially Islam, are almost completely asinine IMO when you lay it all out. I just lost all respect for so-called progressives that still thinks violence is a solution to anything short of like, an alien invasion or some crazy shit. War is fruitless, always has been, always will be. It's still an issue obviously and an enormous part of human existence, but it is never, ever the "right way" IMO. You can cut some slack for our ancestors who had no realistic recourse (although, they did, and used them more we are often led to believe), but in the 21st century for first world countries, there are no excuses).