I would assume "most people" believe the beetles in these fights are fighting to the death (regardless of true risks).
It's been my observation that there is a section of society that gets really upset about the "exploitation" of animals, including insects, for nearly any form of human entertainment. If people are enjoying themselves, somebody, somewhere is going to get pissed off about it. I find such people far more disturbing than the practice of beetle-fighting. This is what beetles do. This is what makes beetles interesting to us. Sure, it's staged and therefore unnatural, but so is keeping them as pets, I say! And I do LOVE a pet beetle!