Just like with a lot of things we have rules against, it's not just your personal data. Encoded in photos of you is data about your family, too. And in public, your surroundings, people nearby you, your location history, etc is all in the realm of these photo systems. There is more data in your photo than just you - this is a societal safety issue.
Allowing a free-for-all in all new tech that has clearly defined privacy issues at scale can cause a lot of runaway problems. A society who tries their best to reduce harm caused by bad actors using wild new technology that has huge privacy implications is a reasonable society to me.
Automated detection of your face matters to the rest of society, too. It's not just your privacy that is affected, it is other people's too.
I don’t understand why I shouldn’t be able to make an adult decision about taking risks with my own personal data.