In truth, Michael, I'm struggling with this too. No one is suggesting stuffing cotton wool in your ears so that you can hear nothing. Now that, that would be impractical. And that's called "ear plugs".
Using proper "ear protection" is another matter entirely. My ER15s, or even a pair of (much cheaper) ER20s, will reduce the volume of what I hear without changing the sound of what I hear.
As a long-term tinnitus sufferer, my understanding is that you can get it just as easily through prolonged exposure to relatively high volumes as by very brief exposure to very high volumes ... I got mine from riding big, noisy motorbikes, not from playing bass.
My point is that regardless of whether you play trumpet, viola or the triangle, playing professionally in an orchestra will require very long periods of exposure to to relatively high volumes.
Of course the guy should have been wearing proper ear protection. I think the question now is whose job was it to supply him with that protection and ensure that he was wearing it.