Yes, rapists should be given harsher punishments. Every person has urges that they need to control for the betterment of society. A rapist physically violated another human being because of their sexual and violent urges. Harsher punishments will inflict more control on members of society that are unable or unwilling to control their urges when it comes to the health and wellbeing of other members of society.
Yes, rapists should be given harsher punishments for the crimes that they commit. People should not be allowed to get away with doing harm to others and not receiving a punishment that reflects this. Rapists should receive severe punishments because their crimes are a severe violation of another person's body.
The vast majority of rapists never see jail time or any kind of punishment for their actions. Rapists should see punishment in the first place. Most rapists are serial rapists because instead of being caught and punished, they get away scot-free and don't see any legal action against them until more and more people are victimized. It's completely unbalanced. They don't need to receive longer jail sentences; they just need to receive those jail sentences in the first place.
Rape is NEVER the victim's fault, but unfortunately, it is a difficult crime to prove. You can have DNA evidence only to find out that the plaintiff lied about her or his lack of consent. Now that brain-reading technology is becoming more reliable, I think that researchers ought to work on developing a reliable sincerity test (probably using MRI).
In the meantime, I think that what we should do to rape sentences is make them more rehabilitative. That way, the sentences are more effective at preventing future rapes AND they don't cause further harm to the wrongly convicted. Rehabilitation is not necessarily soft treatment. The treatment should target the underlying psychology behind rape. Convicts should receive psychological testing to detect impulse control problems, personality disorders, etc. and have treatment tailored to their particular issues.
The sentencing guidelines for this particular offense have been in place for quite some time. Why the need to change it now? Surely if a change is going to be made to impose harsher sentencing, then murder would be a more heinous act. Jails and prisons in the United States are horribly overcrowded. Increasing the length of time an inmate must serve would only add to this problem. Let's deal with the societal problems that exist that cause the United States to have one of the highest crime rates in the world.