This is a false equivalence. Pot smoking is victimless (at most, your landlord will need to get rid of the smell for the next non-smoking tenant). Murder has, by definition, serious consequences for someone else.
In a legal system whose premise is that one should be free to do anything so long as it does not infringe upon the rights of others, it it consistent to legalise pot and keep murder illegal.
In a legal system whose premise is that one should be free to do anything so long as it does not infringe upon the rights of others, it it consistent to legalise pot and keep murder illegal.