The "big book of bacon" subtitle is a joke. Nonetheless, CARBAGE was not written to be vegetarian, but it IS a full-range cookbook, including sections on drinks, sides, salads, main courses, sauces and desserts. So there are many recipes that would work as-is or with minor adjustments for a vegetarian diet. Some, especially many of the main courses, would not be easily adaptable. FAKERY is focused on baking, so there are fewer meat-related ingredients included, but there are some.
Both books also have a strong educational component. A vegetarian would certainly be able to get some use of the recipes, although not every recipe will be practical for a vegetarian approach.