Sutil was convicted of causing grievous bodily harm in a nightclub confrontation in China and given an 18-month suspended sentence Tuesday. Hamilton declined to testify because of commitments with his McLaren team.
Sutil told the Bild Newspaper that "Lewis is a coward, I don't want to be friends with someone like that."
Hamilton witnessed the incident at a party following Hamilton's victory at the China Grand Prix in Shanghai last April, when Sutil cut Renault team executive Eric Lux in the neck with a champagne glass.
Sutil said he intended to spill his drink on Lux, and that causing the injury was completely "unintentional and accidental."