One major problem in the martial arts world is to nail down a philosophy and ask what the goals are for martial arts.
The obvious goal in recent years has been self defense. The simple fact is that , martial arts is essential for this scenario. perhaps one may choose a gun over hand to hand training. But either which way, one is in a position where they are forced to fight.
But really it is not the first cause for fighting skill. Cain killed abel out of murder and not self defense. Probably using techniques acquired when hunting animals is another use. So the ability to produce violence has several applications
Warring parties no doubt were first offensively minded before they became defensively minded. Otherwise they would have no one to fight ;)
So you really have to ask yourself why the violence?
Martial arts as a sport really could be seen back with the ancient greeks and even earlier.
In ancient times to parties would meet and produce to champion warriors to fight to the death. The reason for this was actually rather civilized. The two nations were doing this to avoid a full scale war. that way their wopuld only be one casuality. Without a governing body this was the best possible solution. This scenario is scene in the classic bout of david verses Goliath.
1 Samuel 17
Yet the modern fight sport is designed not decisions of War but instead for the sake of entertainment. At whic point the only gain is money and fame. These things can become intoxicating to the heart however. 1 Timothy 6:10
For the love of money is the root of all evil: which while some coveted after, they have erred from the faith, and pierced themselves through with many sorrows.
also fame is worldliness 1 john 2:
16 For all that is in the world, the lust of the flesh, and the lust of the eyes, and the pride of life, is not of the Father, but is of the world.
17 And the world passeth away, and the lust thereof: but he that doeth the will of God abideth for ever.
So a christian fighter would need more reason than wealth and fame to participate. Perhaps if his money were going to serve the Lord in ministry for instance.