Kenji's videos show how creative and open minded he is with cooking, but I've also had plenty of online encounters with folks preaching the food lab gospel.
Whatever his stuff is, 'whimsical opinion' is pretty rare.
None of this is bad -- the food lab is the cook book most often open in my kitchen and I love his videos -- but develop your own taste and understand the palates of those you're cooking for, don't just assume that whatever Kenji does is right.
But I think “whimsy” is just really off target. Most or his stuff (notwithstanding some retractions, we all learn as we go) is either pretty well researched and backed up or he’ll be very clear it’s just the way he is doing something, not canon. He has strong opinions about some things - especially cookery myths - but they tend to be backed up with a bunch of data, otherwise not so much,
That's why watching his videos is really important. If there's any recipes he ignores completely the most, it's his own.
For example: chinese braised pork belly. Generally you cook the pork belly in the sauce until the sauce itself reduces and coalesceses around the pork belly, giving it a reddish appearance. Then you serve it over rice.
Problem for me?
I'm cajun/creole. While I'm perfectly fine with eating plain white rice by itself in the asian tradition, it's just not how we do it back home. We smother things so that the sauce mixes with the rice. So I added more of the liquid ingredients and brown sugar. I added some korean red pepper to up the pepper flavor of the sauce. I addded some cinnamon sticks because I felt it complimented the other ingredients.
Side by side, my pork tastes a little better than theirs. It's got more flavor. It also has sauce to pour over the rice.
It's not authentic (and not as red), but it's also something that everyone who has ever tried it has enjoyed.
Then again... if I see someone put tomatoes in a gumbo or jambalaya... or sprinkle seasoning on top of seafood after they've been pulled out of the boiling pot... that is a friendship breaker lol.
Now that he's more into videos and his presence is about instruction and eduction through example as opposed to making a splash with authoritative longform pieces and deriving the perfect recipes and guides through Serious Eats he comes across as more welcoming to all approaches but there were times in the past when he pounded the foodie gavel.
If you go through his old recipes though on SE, you'll see "The science of the best XYZ" or "Perfect XYZ" all over the place:
https://www.seriouseats.com/the-food-lab-5118015
I stopped following him a few years ago on Instagram because it was tiring. It looks like he's changed a bit.
Sure, he could put "in my opinion" and "to me" all over the place, but that would just be useless clutter. Everyone knows that "best" when referring to an aesthetic experience is always a subjective matter.