This Can't Be Right

I suppose the sentence for stabbing someone should be greater than for possessing child pornography but this seems very off to me:

A Northampton man whose son stabbed him after discovering he had downloaded child porn has escaped a prison term after admitting his perverted obsession.

Martyn Croft was jailed for seven-and-a-half years at Northampton Crown Court in November after he admitted repeatedly stabbing his father, Brian, then leaving the former bank worker bleeding in his bedroom.