Many many many foods have eggs or dairy products in them that simply don’t need them. The bread for that pbj could very well have milk, eggs in it. Butter on toast is a dairy product. Eggs are a common ingredient in veggie burgers!
That's like complaining about oil products used to patch roads in a discussion about the environmental impact of oil.
That's a huge reason why veganism is growing far faster than vegetarianism. People are realizing the systemic connection between the industries and understanding that all animal products must be eschewed.