There are well documented procedures and protocols for how police and other law enforcement agencies handle hostage situations. Each one differs based on municipality, but each are governed by state and local laws, regulations and all shootings are subject to a thorough review by either IAD or civilian boards (most times both).
SWAT doesn't drive around, constantly on call just in case there's a call. They're also humans and have the ability to think, reason, prioritize and communicate. Drones have none of those capabilities and none of the guidelines, restrictions or review mechanisms in place.
This was a silly comparison to make.