I think there are a couples of problems with how this law was voted.
As you said, the Congress aproved in fast track the Interior Security Law. The problem about fast track voting is that experts in the field and the most affected citizens have not been able to analyze the details of the law. Can there be many unintended consequences? Yes, there can be.
The second issue is the thematic. The military have been fighting drug cartels and criminal bangs to maintain order in the cities. The problem is that crime-fighting is a domestic issue.
This law establishes under what conditions the army can interfere to maintain domestic order. Regulating the role of the military in the cities seems a good idea. However, there are many implications that this law could have. It is necessary to discuss it publicly and not in a fast track way.