1. Wrong practically: it doesn't "purify the human race" in the way that its proponents allege, and even if it did, there remains the fundamental question of who gets to decide how the race needs improving.
1. You can't deny that the child of a criminal will be more likely to lead a criminal life, an idea which is the reason why sterilization works. Also, a democratic government which is representative of its people should be able to decide how sterilization should be used. After all, we already trust our governments with far more important things.
2. Wrong morally: subjecting people to unnecessary and unwanted surgery is a bad thing.
2. However, it could be argued that holding someone against their will in a confined space is immoral, and yet we have prisons. It is a generally held view that criminals have violated the social contract and are therefore not deserving of all the same rights as ordinary citizens (i.e. Liberty). So why not the right to procreate?
I feel that the fact that it takes a surgery to sterilize a person is somewhat irrelevant. If the government could wave their hands and sterilize a person, that would make the act itself no more or less moral.
3. Wrong legally: subjecting people to surgery or other treatment that they have not consented to is against the law in most if not all jurisdictions.
Something isn't wrong simply because it's illegal, it's illegal because it's wrong. However, Forced sterilization of repeat offenders was common practice in the U.S. up until the 1920s, and the court case responsible for the addition of the right to procreate into the constitution(Skinner v.s. Oklahoma, 1927) was won not because forced sterilization was seen as immoral, but because the judge felt the law was unfair, since it did not mandate the sterilization of "white-collar" criminals.
4. Wrong professionally: Codes of conduct for medical practitioners in most if not all countries forbid treatment as in (3).
4. See points 2 and 3.
Seeing, or not seeing "what is wrong" with a proposed act or policy is on one level a moral judgement. I cannot imagine the combination of ignorance and perverted morality that could lead you to see "nothing wrong" in forced sterilization. Thus I conclude that your remark quoted above is merely intended to be provocative.
I am not ignorant, nor am I attempting to be provocative. I myself am not a supporter of compulsory sterilization or eugenics, but I think that it is important to play the devil's advocate sometimes in order to be as objective as possible. You should know that I respect your ideas and your arguments.