How Do You Use Your Judaism?

There’s probably nobody I admire more than my friend (he’s never had a parking ticket!) and the other day he was discussing a bargaining position.
I interrupted: “I love how you use your Judaism.”
I’d said the same sort of thing to him before and he never liked it, which I always found amusing. My friend, who’s far more intelligent, normal, moral, empathic and socially well adjusted than myself, hates the airing of group differences (such as that there tend to be a lot of Jewish and Indian names in Wall Street scandals). This time he exploded at me in front of our friends, accusing me of “deeply anti-Semitic behavior.”
At first, I thought he was kidding.
Luke: “It’s anti-Semitic to say that Jews are good at bargaining?”
Friend: “Yes. You mean it in an anti-Semitic way.”
Luke: “I mean it in the way that I grew up in a type of Protestantism where it was considered vulgar to bargain and to talk about money [and that Judaism makes much more peace with the natural passions such as making money, and therefore Jews have an edge because their religion and culture are more based in reality].”
Friend: “You are the worst kind of anti-Semite. You go around wearing a yarmulke and you say these horrible things about Jews.”
Luke: “That Jews tend to be good at business?”
Friend: “You mean it in a bad way.”
Luke: “Listen you, goy. Why don’t you go study Torah with your lesbian rabbi! I study Talmud every day.”
I’ve got a smile on my face while I say this because I find it impossible to believe that my friend is truly upset, because I know I’m a convert, that he was born Jewish, that he knows more Hebrew than me, that he is smarter and saner and more successful than me and so how could he ever be offended by me. In social status, I am gum beneath his shoe. But I have misread the situation. My friend is out of his mind with rage.
He starts ranting that I desecrated everything Judaism considered holy.
Luke: “Which mitzvah am I violating by saying that Jews are good at bargaining?”
Friend: “Mitzvah doesn’t mean law.”
Luke: “Yes, it does. What do you think it means?”
Friend: “It means good deed. And you are engaging in evil speech. Lashon hara.”
He then goes on to list off all the most embarrassing and vulnerable things I’ve ever revealed and by the time he was done, I think we were all convinced that I was worse than Hitler because at least Hitler was honest, and that I should be utterly destroyed like Amalek.
I was stunned that this guy who I’ve always regarded as such a mentch has no limits when he loses his temper. Everything comes spilling out that could make me look like a worm and all forms of retaliation to destroy me for my perfidy seemed to be on the table for him.
I was raised to fight fair. I’ve never ranted like this against anyone. To win an argument, I’ve never recited publicly what people have confided to me confidentially. In my life, I’ve never gone to the teacher to tattle on another student or gone to the boss to tattle on another employee or gone to the rabbi to tattle on another congregant, so I’m speechless when my friend threatens every connection I hold sacred. I always thought of this kind of tattling as bitch moves. I understand that girls tend not to fight fair when they’re mad because they didn’t grow up getting smacked in the mouth for fighting dirty. On this day, not knowing what to say, and faced with an unfathomable volcano of Ashkenazi rage, I end up apologizing for misreading him and the situation and making inappropriate jokes.