"He should go home, he should go stay in the luxurious house he is staying in," Nel said, citing the defence's argument.
'We shouldn't fail the parents in this instance'
He said the fact that Pistorius would not leave home unless it was to train or go to work and would also do two days of community service twice a month for three years, was not appropriate.
"Weighed up with what he did it is shockingly inappropriate."
He said it was important for the court to "observe" Steenkamp's cousin Kim Martin's evidence and her "real pain".
Martin told the court on Wednesday that correctional supervision was not enough for the death of her cousin.
"We shouldn't fail the parents in this instance."
He said that he will try not to become emotional but that every right thinking person would agree that there could be nothing worse than being at home and hearing your child has died.
"The seriousness of the crime, the interest of society, and that of the victim by far outweighs the circumstances of the accused," Nel said.
"What we have is a privileged person."
Nel said that the evidence given by his manager Petrus Van Zyl that Pistorius would have been a multi-millionaire had the shooting not happened "cannot be an argument".
Steenkamp died a violent death and she did nothing to contribute to her death, said Nel.
"She is totally innocent, she is dead now but she is totally innocent... She had nowhere to go."
On September 12, Pistorius was convicted of culpable homicide for the Valentines Day 2013, shooting of Steenkamp in his Pretoria townhouse. The court found him not guilty of murdering Steenkamp.
Pistorius shot Steenkamp through the locked door of the toilet, apparently thinking she was an intruder about to emerge and attack him. She was hit in the hip, arm, and head.
Pistorius was found guilty of firing a pistol under a table at Tasha's restaurant in Johannesburg in January 2013. He was found not guilty of shooting through the open sunroof of a car in Modderfontein on September 30, 2012, and of illegal possession of ammunition.