I agree with your take on "law" and the concept of, if there is no victim there cannot be a crime.

Also, something can be totally immoral and "wrong" and not be illegal.

Laws created by governments which are not based upon this premise, are constructs which are based in discrimination by those in authority and for those with influence on that authority to the detriment of those which the law affects.

Morality is based on an intrinsic "law". We all understand moral law.
People of sound mind know right from wrong, they may justify their immoral behavior with irrational arguments, but they know what they are doing is wrong, they convince themselves that they have a reason or excuse for putting their selfish desire above morality.