As a pilot, I don't want to bump into a drone of any kind. The actual damage/result is unpredictable. Will the drone hang on to something, will the drone cause damage to my aircraft. Where will the drone end up when the impact occurs? Will the guts end up in the air intake, causing my engine to quit? Will the drone crack a light, will the drone go through the window? F=MA and you can't change that, I am flying at 150mhp, your 5lb drone can do serious damage, bend metal, break plastic, or more.
Even if it doesn't cause a crash, it will likely cause damage to the aircraft. Think of you car being hit by a golf ball. It may break a window, or put a dent in the hood, causing the owner/insurance company to pay $$ for something that the driver was innocent of.
Imagine doing your job, and someone is throwing rocks and your have to go through the area. Sure the person throwing rocks isn't doing anything illegal, but they may damage you.
Fire fighting is dangerous. Firefighting in an aircraft is dangerous. Throwing extra objects in the air near the firefighting aircraft makes the firefighting even more dangerous.
The golden rule needs to apply to the drone operator and the firefighters.