So, to repeat, you say it takes technique.
Technique is skill.
You say not having the technique is not compounded by the weight?
Uh-huh.
I'm bowing out after pointing out the absurdity of that position. If I make a mistake on my bike, yeah, it's heavy, but I can catch it. If I make the same mistake on a heavier bike, it's going to be a multiple worse to recover from that mistake.
-Crissa
Most riders haven't learned proper low speed techniques.
The mistakes those riders make can be "managed" by muscling through if the bike is light enough. I think we are in agreement there and I said so above.
But, "managing by muscling through" is going to fail any rider eventually so learning proper low speed techniques is an important skill to learn (though neglected by 95+% of riders).
Proper low speed maneuvering doesn't require lots of muscle or talent. It might seem so because riding on the street doesn't teach these techniques at all and so someone who is really good on the street but still has to wobble through a parking lot might think that it requires high talent. No, it requires some focused learning.
I don't know if the beginner rider courses teach much of this, but I do remember spending some time learning these skills in parking lots when I took some post-license-level safety classes. They teach the technique pretty well, but you do need some additional practice on your own to really dial them in. And it's something most riders can manage. (And it requires periodic practice as well.)
Once you learn this skill that will help you with lighter bikes, heavier bikes aren't any additional burden. That's what I was getting at.
But, if you don't learn and get good at these skills, then you will need more muscle to correct your wobbles with heavier bikes.