Certainly the prior history information of an apprehended individual is available to enforcement.
Arguments in favor of any form of violence are not supported at all except as sophistry and will always be illegal. Thus it must be discouraged. As violent men are the most likely to cause the most damage, it makes sense to focus particularly on that sector of the population from a law enforcement stand point. It is reasonable to think that the threat of immanent castration will serve to ensure sober second thoughts among those inclined to violence.
Of Course I expect society to have real difficulty ever accepting such an expedient but alternatives are lacking or failing.
And a special nod to Mr Johnathon Swift, esq.