In a military situation, supressive fire is a great tactic.....in a police situation, it creates a hazard for bystanders and opens up departments to all sorts of liability....
....pick the right tool for the job....
I am not sure of the repeated comments that because suppressive is a tactic that can be used by the military that it can't be used or has not place being used by the police. If you are talking about the right tool for the job, it most certainly can and has been used by the police.
That the police should not use suppressive fire assumes that all police situations take place in a context where there are bystanders such as inside of a densely occupied city, that the liability to the police is greater than the risk, and that suppressive fire is necessarily a high volume spray and pray sort of shooting. None of these assumptions are necessarily true or necessarily negate the use of the tactic.
Some may wish to debate the use of terminology between suppressive fire, directed fire, or cover fire, but the intent of use is the same - to keep the opposition from being able to fire for a period of time by putting rounds on his location.