To understand the rules of Buddhism you have to understand them in context and what their purpose is. The purpose of the rules is to help you awaken. If you follow the rules you are more likely to awaken. That's all. The rules are more like laws of psychology (or laws of nature) than laws of a legal system. There is no judgment - it's your choice. If you don't follow the rules, it is not a "sin". You won't be excommunicated from Buddhism. You won't be condemned to hell because you broke a rule. Many Buddhists, like many non Buddhists, believe you could have bad karma if you don't follow some of the rules, eg. if you murder. But the karma is from the murder not because you are disregarding a warning from Buddha that murder would make your mind turbulent and could prevent awakening. Some people who want to awaken agree to follow certain rules and form a group for like minded people. If you don't like their rules, find a different group or start your own group or practice by yourself. There is no pope of Buddhism. Anyone who believes the teachings of Buddha can claim to be a Buddhist whether they follow the rules or not.