Overheard & Wishing I Did Not Join

(overheard)
Student 1: I don't think he's Jewish.
Student 2: Of course, he's not Jewish! He doesn't have a big nose! Look!
Me: Girls, don't say things like that. That's racist.
S2: Say what? (to the other girl) See, he's not Jewish; he doesn't have a big nose.
Me: Don't say racist things like that.
S2: Racist? We're saying you don't have a big nose.
Me: I know. But when you make sweeping comments about a race of people that's racist.
S2: But Jewish people do have big noses.
Me: No they don't. Not all Jewish people.
S1: So, you're Jewish, but you don't have a big nose.
Me: No. I'm not Jewish, but that doesn't matter. (sigh) You can't say that all Jews have big noses, just like you can't say that all black people have big lips.
S1: You have small lips.
S2: Yeah, your lips are really small.
Me: I think my lips are very nice. They have a nice shape. Wait, we're supposed to be talking about quadratic equations.