Fighting is natural.
This is why it exists in the first place.
It is related with a instinctual need to conquer and survive.
It is present in the very core of nature.
Nature created these instincts.
Usually, they have a positive role in human evolution and in your life.
You use fighting to defend yourself and to conquer new territories.
When you educate your children, you'll say things like:
"If someone hits you defend yourself. Don't let anyone put you down"
You ask your children to use their fighting power.
You tell them to tap into this natural instinct.
The same happens with sports.
Competition is simply a form of fight with specific rules.
When you compete, you want to win over your opponent.
With fighting sports, the fight aspect is obvious.
With athletics for instance, you compete for better performance.
It is always a form of fight against an opponent or your own limits.
Fighting and competition are everywhere. They are part of the human spirit.