Most of the time, castration is overkill.
Sometimes, violence solves problems. Periodically, the direct application of force ends an issue before it gets out of hand. But oftentimes, such violence is not the best option.
If you frequent this site frequently, you're likely familiar with this story out of Germany: Angry Father Castrates Daughter's Older Boyfriend
In a nutshell, a man removed the reproductive organs of his teen daughter's MUCH older boyfriend with a bread knife. Like the rest of you guys, I'm tasting bile just thinking about it. Some people, however, find the father to be a folk hero.
Simililarly, a woman in Florida also got in on the action. Per NBC Miami, a woman in the Sunshine State set fire to her guy's baby-making facilities after an argument.
While both the German and the Floridian will no longer be able to use their stuff for mischief, pleasure or procreation, I'm not sure anyone is totally better off. Sure... the German father still says he believes he did the right thing, but a horrific groin wounding is something you usually threaten a guy with rather than actually do. And who's to say the castrato will take his life sentence to pee while sitting down sitting down? Maybe he'll just dust himself off, embrace gender reassignment and still marry the daughter.
In summary, it's a good move to attack a fella's groin if you (or a loved one!) are in danger of immediate bodily harm. It's a bad idea to irrevocably maim someone if you disagree with their approach to a relationship. While we're at it, fellas also need to lay off the physical violence as a way to express their emotional discomfort. Bad Ideas: Cutting Off Your Penis For Love
For a little pick-me-up after the "don't kick me in the balls" talk, enjoy Andy Samberg and Tom Hanks imploring you not to injure their testicles.