I have no problem with vegans who choose it as a personal lifestyle. I have a problem with sanctimonious ones who act like they are morally superior and more enlightened because of their diet. They are like the young-Earth creationists of the left.
Chicken eggs people consume are not chicken fetuses. They are unfertilized eggs. When hens lay them, it's akin to a human woman having her period. They're waste material just like period blood and the microscopic egg discharged with it. I don't see how it's immoral to consume unfertilized animal eggs. People who are pro-life but eat chicken eggs are not hypocrites.
Then there's the types of animals that have no brain or centralized nervous system: sponges, cnidarians, tunicates, and fan worms. Indeed there are species of jellyfish, sea anemones, and tunicates that are edible. I do not believe these animals are conscious or can experience emotions or pain. If you DO believe these animals are conscious and can experience emotions and pain, then there is no reason to assume that plants and fungi can't. Thus, the kingdom of life which a particular organism falls into becomes an arbitrary determinant as to whether or not it's immoral to consume it. It's entirely possible that scientists in the future will be able to synthesize entirely new kingdoms of life through DNA printing. And it's entirely possible that completely different kingdoms of life may have evolved on other worlds; even non-carbon-based life. We could also genetically-engineer very animal-like plants such as ones that move about to search for sunlight, water, and nutrients, and it's possible that such plants could've evolved on other worlds. Indeed slime molds, which are protists, exhibit rather animal-like behavior, at least in comparison to the aforementioned sessile animals. Would it be immoral to consume such organisms?
You cannot know for certain that a non-animal-based substitute exists for every animal-based ingredient required in medications. And by barring the use of animal-based ingredients, you would be preventing new life-saving medications and treatments from being created. For example: https://start1.org/news/a-sea-sponge-could-save-your-life/. You are the one doing lazy thinking.
Moral vegans are just as foolish, sanctimonious, and insufferable as leftists who assert that it's bigoted to not want to date trans people, fat people, disabled people, or have racial preferences (like Riley Dennis).