Anyone mention the outstanding development of biceps that most gymnast have. Not too bad at all, including triceps. They don't seem to spend too much time on curls with BB, DB or cables. All bar & ring work. Gymnast have been know to do one arm work in training.
Back in Yates day there seemed a lot of bicep, pec, etc muscle insert injuries. A little secret was that a overuse of certain drugs (or combo of) was responsible. Yate was using the curl grip row, if I remember correctly, when snap went the bicep. This movement is one of the better lat builders, though offering quite a lot of stress on the biceps.
Still puzzling why such an over reaction to this one arm chinning exercise, from one person. The more he post his fuzzy logic, the more suspect he becomes as to his motives. Sure he may be great guy, meeting him in person. But something happens to a few who come on the internet, the whole persona seems to change for the worse. Good Luck.