I thought it was mean, but really funny.
In awards shows, the host will comment on the recent goings on of celebrites (and, you know, Paris).
Sarah Silverman is an equal opportunity insulter. If, say, Scarlett Johansson was going to jail, Sarah would have probably changed her monologue to include jokes about her.
I don't think she as hurt by the joke; I think she was more hurt by the fact that three quarters of the audience were cheering about the fact that she's going to jail.
Yes, it was mean, but she did something wrong, she seemed not to care and now she's being punished for it.