like boiling anything, the food passes its contents into the water, which usually is considered a bad thing. But with potatos I was told, that it is preferrable, since the toxins too leach into the water. Dont reuse this water to make stock or some such. Discard.

But I just prefer to stay away from them.

Personally, I try to avoid them all, but will eat peppers or tomatos if they are well ripened, and when in season, and try not to eat a lot of it even so.
This more relaxed approach stems more from TCM mixed with "Eat right for your type"- kind of a thing, where certain foods are considered bad for one certain person, or bad in a particular season. Might not make much sense to anyone else, but works fine for me.

In my opinion this kind of very critical way of looking at food (which in fact in this case is forming the staple food for whole populations, i.e. south americas etc, I think it is better to apply common sense, than just stick to a hard and fast rules. They are more like guidelines really, and a person should consider if the food fits the climate, season or personal needs. My friend who gets terrible indigestion for example, I would recommend never to eat them, as it is clearly a warning sign. For other people, who do not show any signs of incompatibility, I would consider caution within reason, as sometimes illness only occurs after years of consuming a slightly toxic food.. so long term effects could be the problem, which would also explain why it is so hard to prove a clear connection between such a food and disease.

I ramble, hope this helps.