Asking a vegetarian if they mind me eating meat when I'm with them is just showing consideration. I know some veggies who have a hard time with seeing people eat meat and it's no skin off my nose to make a friend comfortable. I generally don't ask any more. The friends I have who don't mind, don't mind. But, there are friends of mine who I know are uncomfortable with it, so I just eat veggie when I'm with them. Not a big deal.
The key with Ruby's situation is that she's an addict and seems to barely have her addiction under control. Just out of consideration for her, I would have cut the really fatty dishes from that meal. Plus, as someone pointed out, she ate a lot while preparing the meal. I would have pushed her out of the kitchen and told her that she didn't have to prepare anything since she provided her house.
She did say she would only eat 2 tablespoons of each thing and it looked more like 2 serving spoons. At least.