Thing is you only need a ball. And it can be played from 1 player onwards to any number enough space provided. And it combines artistic abilities, fight, speed, muscle, will, team and individual skills. So many find it appealing. But the pro leagues all have one problem: greed, doping, injuries and corruption. Not to mention that it is used as a nationalistic means, propagangda tool, war replacement or even as a casus belli in a few cases in southern america. Also it is used as a background ideology for people to organise violence and even political uproar. Same as in ancient roman Empires. The fighting sports mingle with politics and ideology.