GZ went beyond "watching."But GZ was neighbourhood watch and had no idea that TM would try and ambush him. And Stanley was defending his property.
TM and Boushie died because they made choices which were even worse than Zimmerman and Stanley. TM was trying - arguably - to kill GZ. Boushie was invading Stanley's property.
As for defending property is it legal to go get a gun and point it at people stealing your ATV?
Yes the dead boys made bad choices but it didn't mean they needed to die. BOTH sides were wrong. As I stated in an earlier post if TM and CB survived they too should be charged (obviously for different offences).
IF GZ backed off when he was told.... both would be alive.
IF Stanley took pics with his phone and backed off the cops would follow the plates of the car to one of the natvie's home and they recover the ATV. If damaged Stanley would be getting insurance money and Boushie would be charged with theft.