Organic chemistry: the study of carbon compounds.
Biology: the study of carbon compounds that crawl.
How does tracking a vehicle you own impact someone else's personal safety, especially a thief?
The personal safety issue isn't about tracking a vehicle you own. Apple put the speaker alert there to prevent other people from tracking you without your knowledge. Think about scenarios such as bad divorce, ex-from-hell, or any other form of stalker slipping an AirTag into your purse, backpack, or car.
Does it really matter if there's enough in local areas to achieve immunity?
Yes, it matters. Large populations of unvaccinated people put vaccinated folks at risk in the long run via two mechanisms. The first is that they are a breeding pool for the disease, providing it with more opportunities to mutate into vaccine resistant or more lethal or communicable strains. (If you haven't ever seen this video, it's an eye-opener.) The second is that they are a reservoir of the disease which will periodically spill over as vaccine efficacy declines after a couple of years, or as vaccination rates decline in vaccinated areas when people in those regions become less aware of the risk (as happened with measles in the US in recent years).
To be or not to be, that is the bottom line.