You appear to be using the word “freedom” to refer to something other than the ability to act without constraint. The phrase “My freedom ends where yours begins” (and its many variations and false attributions to various famous figures) is one of moral considerations and generally used to argue for what the world ought to be, but it is not and never has been a fundamental — i.e. even when the law falls silent — truth of the reality we actually live in.

The same is true for selling poisonous baby milk or wine.

Laws "cannot allow murder"; murder is illegal by definition. For example, if two hypothetical killings take place under identical circumstances but under two different legal jurisdictions, the killing could be considered murder in one place but justified in another. This happens all the time, see Florida's stand your ground laws for instance.