I was a little confused by the use of a metaphor. You used hands because there are five points, yes?
correct
It would have been just as useful with the points numbered, the fingers just seemed gimmicky to me.
well, the metaphor goes a bit further than that. The thumb (rule universalism) is an abstract principle because it does not say which situations are morally similar. To answer the question which situations count as similar, we need the other principles, the other fingers. Metaphorically speaking: with only a thumb we cannot yet grasp anything. With only the thumb principle we cannot yet grasp a moral problem.
The middle finger is longer than the forefinger, which means that the basic right is a bit stronger than well-being. For example: we should not sacrifice a person, kill him against his will and use five of his organs to save the lives of five patients in the hospital when there is a shortage of organs. So the right not to be killed and used against your will as a means to someone else's ends is at least five times stronger than the right not to die against your will. But the middle finger is not infinitely long: the basic right is not absolute.
And the little finger refers to a small deviation from the other fingers, to a small level of partiality that we should tolerate.
As for veganism, if the whole world went vegan,it would be good for co2 emissions and food production levels, but it isn't going to happen. I won't stop eating meat, nor will billions of others. Eating a complete vegan diet is difficult, those who say it isn't are lying.
the more people eat vegan, the easier it becomes. The only difficulty in our societies is the group pressure from non-vegans. That is the main reason why vegans experience difficulties. Practically speaking, veganism is easier: less expensive (meat is expensive), more healthy (meat has more saturated fats and bad cholesterol), sufficiently tasty and diverse (in the supermarket and health food stores I can buy then different kinds of plant-based milk) and more hygienic. Meat is contaminated with pathogens; you don't run the risk of a food poisoning when you don't cook your vegan sausages. So, cooking vegan is in fact easier than cooking meat.