Legality is, in general, a matter of fact. The legality or constitutionality of a matter is determined in the courts.
Morality is a matter of opinion, and, I believe, pretty much independent of legality.
That means a law can be both immoral and legal, depending on your perspective.
Policing technology is a constantly evolving marketplace and technologies that strike some as immoral frequently are tested in court where their legality is determined.
Many folks weighing in see the act of developing Stingray technology as an immoral act, and it seems that thereby, those who engage in such development are immoral people.
In my opinion, labeling others as immoral for engaging in something you don't approve of is a double edged sword and the more you wield it, the more jeopardy you put yourself in. Anyone who works for a mainstream technology company can have that same finger pointed at them for some facet of their employer's actions.
People who believe that this technology should not be deployed would find it just, if not moral, to pursue a political change rather than shaming those who see a valid purpose for what they are developing.