The short answer is that there is no definitive answer, as there is no research that definitively indicates whether 100 pull UPS a day is good for you. However, based on the available research, it seems that a moderate amount of pull UPS, such as 50-100, may be beneficial for overall fitness and strength.
Additionally, some people may find that increasing their pull up routine to 100 or more per day can be a great way to challenge and stimulate their muscles and joints. Ultimately, the answer to whether 100 pull UPS a day is good for you depends on your individual fitness goals and preferences.