There are some reasons coming to my mind:Varied Exercises
he said he doesnt benchpress, but maybe he is doing other exercises for his chest, just to balance things out. When you mention russians as far as i know they follow more of a "get-strong-all-around" mentality meaning that they try to get strong at more movements than just the olympic lifts like the bulgarians do.
The Russians and Bulgarian (athlete in general) utilize a variety of exercise to increase strength.
With that said, varying the exercise can be as simple as changing the hand spacing or foot position in the movement.
Research have verified that anecdotal evidence that changes in movement will increase strength.
It could also be that he did bench presses or direct chest work in his younger years. Genetics? Both of those are probably true.
Another reasons Olympic Lifter do not preform the bench press is because it decreases flexibility in the shoulders.
Extreme flexibility in the shoulders in necessary for the Snatch.
Steroids? I`ve read that they also increase muscle mass in men who dont train, Steroids
It doesn't quite work that way.
Sitting on a sofa, watching TV and eating Dianabol tablets like "M&M" minutely increases muscle mass.
For them to really work, hard training is mandatory.
An example of this is a study that demonstrated...
Couch Potatoes Grow Increase Muscle Mass
Couch potatoes who sat watching TV and consuming a lot of calories actually grew muscle from NOT training.
That the good news.
The Bad News
Twenty percent of their weight gain was muscle.
The remaining eighty percent was body fat.
Or maybe its not even needed and just grows as a byproduct of all the olympic variations. (another example would be sprinters and their muscular arms)Good Point
There is some over all increases in muscle mass when compound movement are employed.
That why one of the old adages is, "If you want big arms squat!"
However, some direct work is necessary.
Sprinters who increase upper body strength are able to propel themselves down the track faster.
A way of testing this is to perform a sprint without the use of your arms. Keep them pinned to you side.
Then preform the sprint with you arms.