The fact is that beekeepers who treat their bees with chemicals are still losing colonies in a similar ratio to those of treatment-free beekeepers.
What I believe is that, over time, raising bees without treatments produces hardier bees. Treating bees with chemicals helps the bees that have weaker “genetics” to continue to propagate and allows the strongest mites to breed more, stronger mites.
One common argument that beekeepers who treat their bees will continually bring up as their first or second defense is the notion of “mite-bombs” in correlation to drifting and robbing. Yes, drifting of drones into other colonies does occur and robbing of weak colonies does take place regularly. But, try thinking about it this way… even if all the managed hives in the world were treated, the feral colonies that exist out there (and believe me… there are a lot) will still remain untreated. If a feral colony happens to begin dying of mite infestation, there is nothing we can do to stop the spread of mites from taking place anyways.
If you are a treatment-free beekeeper and you are afraid of being labeled unneighborly or irresponsible, do not be dismayed. It just comes with the territory of standing up for what you believe and standing up for science. I’m here to tell you that you DO NOT need to feel all alone and you can feel secure in your beliefs.
Contrary to the supposed wisdom of the “mite bomb” theory, mature feral colonies and established, overwintered, treatment-free colonies are actually “mite black holes” or “mite vacuums” such that when mites are brought into the hive, they don’t leave alive! These hives actively eliminate mites from the environment and having them in the vicinity of other hives is good for the population, as they contribute to herd immunity.
Beekeepers across the United States lost 33% of their honey bee colonies during the course of the year spanning April 2016 to April 2017. Winter loss rates were at 21%, while Summer loss rates were 18%.  For the year of 2015-2016, over 44% of colonies were lost over the course of the year. Winter loss rates were near 28%, and Summer loss rates were also around 28%. 
If your hive dies out in winter from mites, the mites will already be dead by the time other colonies come around and start robbing, so, this supposed “mite-bomb” issue might not even apply for a portion of the year in colder regions of the world in the first place.
The national Bee Informed survey also shows that losses sustained by non-treating beekeepers was nearly the same as losses seen by treating beekeepers. As I’ve stated before, in another article I’ve written … if there’s not much of a reported difference in loss, why not just save your money and stop buying chemicals?!
In closing, one more point to mention is… if your colonies are not susceptible to mite infestations (if they have become mite-resistant) they can not become mite-bombs. In many treatment-free beekeepers’ opinions, the true source of mite-bombs are actually the treated hives that can not deal with Varroa on their own accord. These are the colonies that are fail in the Fall due to heavy mite load even after being treated and then become susceptible to robbing, which, in turn produces the dreaded and supposed mite bomb.
So, is it really unneighborly or irresponsible to not treat your bees? You tell me!