I am not trying to defend those sherpas' violent reaction. There must have been other ways to deal with this. But this white swiss prick who thinks because he climbed other mountains without rope, he can do the same in Nepal needed to punished. There are rules and guidelines to climb mount everest. He should respect that even if he does not like it. These Sherpas risk their lives to make these westerners' climb as easy and comfortable as possible. Sherpas in return are paid generously, there is no doubt. But to go against what had been advised is to invite problems. But definitely, the sherpas were wrong to beat them up.
There are other ways to stand-up against arrogance and sense of superiority shown by westerners.
They could have simply banned these climbers for life from climbing nepalese mountains. But do they have brains?