I think it's all about being in "the know" or not. It seems to me that it's human nature to become so familiar with "what we do", that there comes a point when we will decide that there is nothing left to learn. Like it is pointless to continue to get new opinions or explore new ideas because we already know eveything that there is to know about "what we do". When we, as humans, naturally get to the place where this happens, we often actually fall behind.
Take, for instance, the fact that people who have departed from the Langstoth hive and have moved to Warre hives have found that there are many advantages for the bees. The bees in Warres consume fewer stores in the winter, stay warmer and drier, don't pass stores on their way up, live in fresh wax which helps prevent numerous diseases and swarm much less frequently. People who have used these hives know this to be true. Warre, who was a commercial honey producer, knew all of these things 100 years ago. Yet most beekeeping suppliers and commercial beekeepers that I speak with have never heard of Warres or they dismiss them as simply a "hobbyist thing that has no real advantages".
Another example is what Michael Bush has been saying for some time. Small or natural cell size combats varroa. Everyone wants proof before they'll try it, rather than trying it to see if it works for them. Those of us who use it know that it works.
The beekeepers who don't believe that you don't treat are stuck in the "knowledge" that you simply must treat with chemicals for varroa or your hives will die off. The fact that they still lose some of their hives is proof of this to them, when the reality is that they may not lose more hives than they do now if they stopped using chemicals or that they might lose even fewer hives than they do now if they would just adopt better beekeeping practices.
Now, someone asked about whether powdered sugar was to be considered a chemical. I say no. I think treating with powdered sugar is OK, but if I had a hive that had a frequent problem with varroa I would simply stop treating it and let it die if that was what was inevitable. I also like and use HBH. I won't make any claims as to what I think it does or does not do, but I think that it is good for the bees, I like it, and I feed it a couple times per year. I don't consider it to be a chemical, either.
Chris Harvey--Teakwood Organics