I think you are right about that. Certainly it is an added effect. The part he didn't mention in this is the role bile plays in removing substances from the liver. That happens even when you don't use your gallbladder. This is what makes the increased concentration of cholesterol in your bladder. If you are not moving that out regularly then precipitation happens. And as can be seen when trying to grow crystals in the lab, time and concentration are the main factors there.
Of course, none of this explains why I have gallstones. I believe in my case it is a failure to produce enough bile in the first place. I'll be taking bile salts but also looking in to bitters, because, yes, I avoid the bitter flavors.
Also not mentioned here, if I recall correctly, is fasting. One of the things you can do is not eat until your bladder is completely full of fresh bile, then make sure it completely empties. This gives a greater opportunity for dissolving the stones. IF is great for that. Again, this doesn't explain why I have gallstones... but I'll just cover that cognitive dissonance with some confirmation bias.