The very first thing about United States jurisprudence is that the law as applied is often subject to all sorts of permutations that don't make a lot of logical sense, and certainly the law as currently utilized is absolutely no deterrent to certain crimes, because the very people perpetrating such crimes, are typically clueless of the consequences and costs of such crimes, and in reality don't become cognizant of the extent of the punishment that they are susceptible to, until the charges are made by the prosecution.
As for the law, and specifically when it comes to violent crimes, most laypeople, would consider that for a person to be convicted of a violent felony that the crime would have to be both violent as well as also being categorized as a felony. So that, most people would readily agree that murder, aggravated assault and battery of a high nature, and kidnapping, would all be rightly classified as being a violent felony. However, it must be said, that some criminals are not successful at what they are attempting to do, so that attempted murder, in which the victim is not physically hurt, is still considered to be a violent felony because the perpetrator was attempting to murder the other person. So then, we find that in many cases crimes that are classified as a violent felony, still are in force, even when the perpetrator isn’t successful in carrying out their actions, solely because the perpetrator was trying to commit a crime categorized as a violent felony.
Additionally, the same type of crime can be classified differently in different States, along with the fact that some crimes are categorized as violent felonies, which don't seem to have an element of violence attached to them. For instance, drug trafficking of methamphetamine is considered to be in some States a violent felony, even if the other party is a willing buyer of that methamphetamine. So too, arson is considered a violent felony, even when the violence so perpetuated is upon an abandoned home or building. Additionally, aggravated voyeurism is a violent felony, even though there is no physical contact between the perpetrator and the victim
The problem with violent felonies, as currently adjudicated, is that higher courts have ruled that a violent felony can exist, when someone threatens another, or in which a criminal action contains the element of physical force. This so signifies, that because most felonies involve the use of some sort of degree of physical force, as in the taking of something from another, such then would signify that a person having their iPhone pick-pocketed from them, could thereby be interpreted as they having suffered from a violent felony.
The reason that it matters whether a crime is considered to be violent or not, is that the punishment for violent felonies is almost always considerably more than the penalty for the same type of crime but without the designation or classification of being violent. So that, in New York, for instance, a 'C' or a 'D' violent felony, necessitates mandatory incarceration; whereas a 'C' or a 'D' for a non-violent felony, has the option of the perpetrator being sentenced to no jail or just probation. All of this basically means, that violent felonies that don't involve violence but are prosecuted as violent felonies, are laws that have been molded into punishing people more than what it is really fair, and clearly is done so in a manner that is both arbitrary as well as unjust.