I suspect all bees can handle mites on their own if other stressors are removed from the colony.
If this were so, feral bees would not have been nearly wiped out in the U.S. 20 years ago and would not only now be recovering. There is a clear genetic component to mite tolerance. See John Kefuss' writings if you want to read what others found. Most commercial bees do not have the genetic basis to survive much more than a year.
Elgons were touted as mite tolerant for a few years, but the clear evidence is that they are just about as varroa susceptible as pure Buckfast. If you want more detail I have Erik's email around here somewhere. He is still working on mite tolerance, but the bees are not there yet. Russian bees definitely have the genetics to make it, but there are a ton of negative genetics in the mix such as excessive swarming, defensive stinging behavior, and extreme brood shutdown at any pause in pollen availability.
I don't claim to have kept all species of honeybee, but I can name all 28 currently recognized species and describe where they are found and what their basic traits are. I can tell you which have been challenged by varroa and which are still unexposed and which four have demonstrated significant tolerance to varroa. I can also tell you that Russians are not a race, they are a hodgepodge of bees that were imported into eastern Russia over 100 years ago.
Yes, I guess I am bold. I made a decision 21 years ago to find and propagate honeybees that are resistant to varroa. I found the first moderately resistant colony in 2004 and built from them to the bees I have today. They have their flaws, but they are alive and they make a crop of honey each year and they overwinter with very low loss levels. My bees have survived and thrived for 8 years untreated. I have most of them on small cell, but keep 3 colonies on large cell just to show that it is not the cell size that allows them to survive. I've lost 2 colonies so far this winter. One was a purchased queen that never built up enough to make it through winter, the other went queenless in late fall. I deliberately let them both die though I could have combined them with other colonies and claimed zero losses. Neither died from varroa.
It might help to remember that we each want other beekeepers to figure out how to go treatment free. So instead of going ballistic and thinking I am challenging you, think through what you are doing and why and what message you would like to give to other beekeepers.