I personally am skeptical of the idea that sunscreens are actually responsible for marine ecosystem changes, rather than climate change or other large forces. The majority of a chemical sunscreen formula is inert base. And we’re talking about thin films of sunscreen diluting into a vast body of water. Further, most people at the beach are using water resistant sunscreen, further reducing the potential for harm.
Sunscreens are really valuable technology. They prevent skin cancers and sun damage, and I think policy should err on the side of encouraging their use.
I further think that reactive, feel-good measures like banning straws and demonizing sunscreen do much more harm than good, because they cause fatigue and apathy about environmental issues and do little to solve them.
The political will to solve problems is a finite resource. Squandering it on trivial crusades is, IMO, one of the most wasteful and harmful decisions that could be made.
Trivial to some upper class person in an air conditioned home who doesn’t want to think about bad things and who’ll survive no matter what is certainly not trivial to billions increasingly struggling to survive with no way to escape to greener pastures.