Anything biological is going to have some negative and some positive stuff in it. Most of this is not going to cause a problem for wine. Small charged things are dissolved in the water and are clear. Bigger things, like the skeletons of dead yeast cells, are heavy enough that they settle out on their own within a few months at most. It's the mid-size things that can be a problem. Some proteins fall into this range, as do some larger carbohydrates, like pectin. Sometimes you have glycoproteins, which are proteins and carbohydrates stuck together.
Carbohydrates are generally negative. Proteins vary in charge, and their charge changes depending on the pH. At the pH of most wine, most proteins are positive. So the carbohydrates and proteins can stick to each other in clumps big enough to settle, and can theoretically help clear each other.
Red wines have lots of tannins, and tannins are negative and do the same thing that bentonite would. So if you have a red wine that is cloudy, it probably needs a positive clearing agent like sparkolloid.
White wine made commercially is usually treated with bentonite, so I suspect that the problem with white wine is more often protein. You can add bentonite and see if it works, and try sparkolloid if it doesn't.
If you add both a positive and a negative clarifying agent, they do stick to each other, but that's not necessarily bad. The goal is not to get one bentonite molecule stuck to one protein molecule -- that's still too small. You want big aggregates of some positives and some negatives. One positive thing can bind to more than one negative thing and vice-versa, so that you get a complex branching thing. The bigger the clump the faster it falls.
Personally I don't use any of this stuff unless I absolutely have to. I'm worried it will affect the taste.