It's worse than that. Much worse. Local cops wanted to stay cool.
She may be an incompetent moron, but that she took the hit for the local cops is perhaps her one minuscule saving grace.
Whoever the snipers asked permission from to neutralize the shooter - and who denied that permission, reportedly - would have known there was no SWAT team on the roof.
Also, no SWAT team ever would be dressed like this shooter was, and the scopes the snipers had would have made it really easy to know this was not LE on the roof, which is why they requested permission to take out the shooter.
The big question is who denied the permission.