Is it wrong that I used to maliciously tackle people in highschool football?
Why did you maliciously tackle people?
Yes, It's because I was taunted really badly after being hit by a fast car.
Good sportsmanship includes being able to win without gloating, respecting one's opponents, and being able to lose gracefully. Unhealthy aggression leads to penalties, suspensions, unnecessary injuries, and possibly legal consequences.
Yes, but if you are hated by your opponent you will succeed.
You should not strive to be hated by anyone, rather you should want to be respected. But violent acts will not help you to gain respect. This is wrong and unnecesary.