I think there is a world of difference between what was done by Chelsea Lately and SNL.
Chelsea made fun of something she was entirely ignorant about, thus truly insulting Deaf and our language. I think she got what she deserved when people erupted against her. I think she owes an apology for being rude.
SNL, on the other hand, showed a very playful nature, and I think they did a parody in good humor and with a fair amount of knowledge. I found the ASL part pretty funny, the Italian party absolutely hilarious, and the Spanish part really funny too. It's just my opinion, but I think if you're offended by the SNL skit, you may want to grow thicker skin and laugh along.
I'm open to comments as to why it was insulting. Marlee's opinion carried no weight with me, though.