I am not a physicist, either; but I do have some training. Static charges are not always + or always -. The polarity varies depending ob the material's position in the Triboelectric series:
https://www.alphalabinc.com/triboelectric-series/As we can see, vinyl/PVC is quite low in the table and acquires a negative charge when rubbed with metal, as do the majority of materials in the table. Diamonds don't appear in the table; but both diamonds and vinyl are not conductors, so any charge built up on the LP will not easily drain away. My experience with conductive brushes has not been all that good, so I eventually bought the Milty. I resisted for a long time, because I had a Zerostat gun back in the '80s, which worked pretty well but wore out and was not as expensive as the Milty, which I consider overpriced. From experience I've found that directing only the release stroke, which I believe is the one that emits positive charges, at the LP is more effective than both the squeeze and release. If a little Thorium emitting positive charges in the vicinity of my LPs (but NOT my cartridge) helps, and it seems to be, I am all for it. Especially because it is totally passive. I don't have to do anything after I place them on the plinth. I'll let you all know If I see any change in results.
PS. Pfan-Stat works by leaving a very thin conductive coating on the LP. I tend to avoid it; but it works pretty well when I use it. It makes those conductive brushes work much better.