It is a matter of prospective, and hers is not any less valid, but Castiel would not call the flirting pointless. He can understand it better when she puts that way. Love is a human concept that he himself finds he desires too. And humans have a habit of placing affection on the labor they do for others. "I think I am beginning to understand." He nods. "Next time, it would please me greatly to make you a dish."

She's being very clear... just like how he is being very clear with her. In his record keeping of events, he is not offering anything close to assurances as he only knows it as the truth. There's a lot he needs to work on to understand people in general to be less of the clueless angel he is. Yes, food is very appealing, while she takes her time to think about, he slurps up some of the noodles, using the fork more as bridge to his mouth.

"I'm not sure I follow what you are trying to say. But if you do not want to have sex anymore, then you are more than free to do so." Oh Cas, grab a clue. Lucy is not saying that at all, though he can't hide a new sense of deflatedness. "Whatever you decide, I'm still interested in maintaining a relationship with you." So where does that leave them?