Well, lying is widely regarded as unethical in most circumstances, but is criminalised only in very limited circumstances. Adultery is widely regarded as unethical in many, most, or all circumstances, but is not criminalised in any circumstances. Many people regard prostitution as immoral but in fact it's not a crime where I live, or in many countries (though of course it is in some). And these examples could be multiplied almost indefinitely.
These are not examples of logical consistency, but simply an observation of human behaviour and the current legal system. People can be, and often are, illogical.
The acts which we seek to forcibly prevent are in fact only a small subset of the acts that we consider unethical. Even if we conclude that a particular act is unethical, the question of whether it should be forcibly prevented raised a whole host of new ethical questions regarding the use of force, the limits of personal freedom, the role and power of the state, etc, etc.
There are two points here, I think. Firstly, I did state above that if one thought situation X was morally wrong, they should prevent it if able
. The act of policing everyone is perhaps something that we are not able to do, but should we come across an immoral act that we are capable of preventing, we should
, as I understand the definition of ethics, try to prevent it or correct it.
Secondly, if one is not convinced of a moral position, as many people are about many positions, then they cannot say that this is what they should
do. So if someone knows they should
prevent something, but are not sure how
they should prevent something, they also may be unable to proceed.
If something shouldn't
be done (i.e. you understand this to be immoral), you have at your disposal everything but those things which shouldn't
be done to prevent it, and should
act one of those out, if it gives you the possibility of preventing it. This may, or may not, according to morals, include the use of force. But it is distinct, as I understand it, from letting something immoral occur because someone else is doing it.
In the case of spending money, the use of force is not as applicable. There is a legal system which already defines what we may legally and illegally spend our money on, and it is probably through this that changes would be best effected.
It is perfectly possible, logically consistent and extremely common for an individual or a society to take the view that action X may be or definitely is unethical, but that the individual, or society, has no right forcibly to prevent it.
If ethics is about should
, then this implies a right to carry out the should
. It is illogical to say, "I should
do this [save the pram from the train] but I have no right
." The should is a right.
If there is something that you believe you have no right to do (i.e. stop someone from committing suicide, say) then you have no moral stance on that situation.