No, they are not acceptable.
In my experience, some gray actions and decisions could be morally correct for the individual good. That rarely happens for the greater good. Usually I find that what some people call grey actions or decisions is nothing more than incomplete or lazy evaluation.
An example is police work. An officer may present false evidence to convict someone he deems guilty. You may think the officer did a service to society, but that is true only assuming some facts. The first fact is that the person is guilty. If an innocent goes to jail, the guilty is free to keep a life of crime. Another fact is that the convicted will not notice the false evidence, and most likely he will. If he is like some ex-convicts I know, he WILL seek revenge on the officer once he is free. At least, the ex-convict may keep a life of crime but of a different kind. What reforms a criminal is not only jail time, it is the awareness that he might get caught. If a criminal thinks he got caught fair and square, he may not try again for fear of getting caught. If he thinks he got caught by fraud, he may think he may be luckier next time.
I can keep going, but my point is that many people would only see that the criminal did time and not see the ramifications,