I didn't pay for it because I was busy and I'm not a boxing fan.
But who the **** do you think chose to pay $100?
The people who paid did.
Just because you think they shouldn't, doesn't mean they shouldn't be allowed to.
And what was their alternative? They didn't set the price and won't set the price on future fights.
Imagine you are an Arsenal fan and as a kid you went to every game. You grew up, got a job and continued to go to every game and your low paying job allowed it. Then, 20-30 years go by and ticket prices are ridiculously high. You have an importance to go to see your team play so you scrape the money together to get there. This is one example of sport not listening to fans and putting prices up whilst taking advantage of the supporters who just want to see their team play. Boxing is no different and it is a massive reason as to why it is dying out. This fight probably put a bigger nail than usual into it's coffin.