Yes, you're completely right, they are very curious and are in large numbers. I do believe they are an automated (AI?) drone-like tech that are left to monitor all earth creatures at a large scale.

Like you said, they are curious when we perform animalistic activities, like having sex and fighting (I noticed they appear a lot in CCTV footage where people are shot, fought and killed).

I also believe that these orbs are the ones responsible for paranormal poltergeist activities, such as things moving on their own etc... I do believe they try to mimic human activity to an extent.

I even speculate sometime that they are responsible for ghost sightings, as they could have the tech to induce hallucination on humans, maybe to make us flee, or to study our psychic response.

Anyway, enough speculations, I think that if we have a shot to study UFOs it is only with these small ones. Because if they are automated, maybe (finger crossed) we can elaborate scientific experiments to trick them, and study them closely. Otherwise, I don't believe we can apply science on conscious alien beings that are smarter than us.