Why do they have these rules for Halal and Haram?

Halal means good stuff and haram means bad stuff

So they have these rules to tell us what is good from bad

Like alcohol is bad so it is haram

Pork is also haram because it contains lots of pathogens that cause diseases if not cooked properly.

Also halal refers to a way of doing things for e.g if money is earned in an honest way it is halal and if earned in a dishonest way then haram.