1) There was a drop in crime, yes, but there were other cities that saw equally large drops in crime without stop and frisk. Also, the NYPD implemented and improved other programs at the same time it was implementing stop and frisk. So, it’s hard/impossible to determine the extent to which stop and frisk lowered crime.
2) By your logic, it seems that any effective program would be constitutional. That’s simply not the case.
Many American cities with large populations of Blacks and Hispanics have huge amounts of crime due to those groups. But every area is not necessarily the same. El Paso, which has an overwhelmingly high percentage of Hispanics, has a very low murder rate. Stop and Frisk is not necessary in El Paso.
What are the rights of the people who are not committing large amounts of crime? Are they supposed to live in fear and danger from the criminal element because the latter's constitutional rights are supposedly being violated? I think not.