Surprised no one's mentioning this contradiction about Llewyn

Well spotted..
I reckon Llewyn is emotional and unsure of himself and generally says things that stuff things up for him. He pretty much always says the wrong thing. He's not fussy if he contradicts himlself. He doesn't know what he wants.

That kind of makes me wonder was he having a tirade against the Gorfeins or an inner tirade?

Was the part of him that did it for the love of singing having a knock-down drag-out with the part of him that just wanted to be able to buy a winter coat?

It's a bit deeper than that:

1) He didn't like that she sang Mike's part and obviously, he still hasn't gotten over him.

2) You're right, but he needs money and he wants to earn it doing something he loves. I don't think he appreciated how the Gorfeins used him in that dinner.

A character having contradictions isn't necessarily a negative.

Do I have to give it to you?

The contradiction is so obvious that it was definitely intentional, thats if youre trying to argue that it was a "goof" on the Coen Bros part

I tend to interpret things from Llewyn as I would from a person in real life, meaning that I can totally accept that they contradict themselves and that I'll never really know if I completely understood them, so I may end meandering a bit here!

In that scene I felt that Llewyn seemed sort of cornered. He's angry and grieving, sure, but he's also asked to perform in a way that removes the barrier between the artist and his public, or between the professional and the amateur. I think he's ready to bare his soul in a performance, but he's got no interest in seeing others doing so, argh, that's hard to express. He's not one to play for friends around a campfire, you know? He's there for the music, not for the catharsis.

Also, as a whole he seems to judge others easily, quite perceptively and not at all mercifully, so he certainly sees the quirks and ridiculousness of the Gorfeins that the Coen bros show us. And when Llewyn doesn't like something or someone and feels bad about himself he tends to lash out, as we see in other scenes.

So I read this as him finding the answer that will hurt Lillian the most and contradict her sentence about "a joyous expression of the soul" the most completely. It's provocative and painful and I think that he hurts himself saying it too, and knows it. Something a bit masochistic, and a bit like prodding a wound to see if it hurts.

I think it's a well-spotted observation. It raises two points. 1. This perceived contradiction gives a whole new layer of nuance to Llewyn. Perhaps he has become cynical and prone to self-doubt at this point and has compromised his previous integrity. There is also the potential that he was just parading over Jean with his moral superiority while secretly being jealous of her success.

2. If this is a contradiction, very rarely does the person see their beliefs and actions as contradictory. He may not be in it for the money, but he may want his music to have a certain performance quality that is not found at a casual dinner party. Moreover, he may not find the environment of the Gorfein's to be conducive to the kind of performance he wants to do. He might want to be a cultural icon, not an after dinner entertainer.

My favourite scene is the one in the Gorfein's. As someone who has done stand up comedy I relate. When my friends ask me to tell a joke at parties. I was never in it for the money but no one likes bearing one's soul at a moment against their choosing. Also, most creative people are selective in who they want to perform to. You want your craft to have some significance, not just be a tap you turn on and off at people's pleasure.