I go out of my way to feed the grackles and starlings. I am only just learning about starlings, but both grackles and starlings eat insects, LOTS of insects. Personally, I'd rather risk a little bird poop that can be wiped off, than a hundred mosquito bites.
Calling for the elimination of two species of birds in a city is just arrogant and stupid. Grackles makes the most lovely sounds, I've spent hours learning to copy their "chack" sound, and starlings learn to speak, mimic cell phones, and theme songs.
Killing highly intelligent creatures is wrong. Don't like the bird poop? Stay inside. There is nature outside.