People wear sunglasses for lots of reasons, many of which are none of your business. They might be vision-impaired, have glaucoma, have dilated pupils from the eye doctor, or just be really hungover.
You’re not in charge, leave people’s clothing and accessory choices alone.
Come on, buddy. People may want to wear helmets for all I care. Doesn't mean I'd super eager to talk to them
And some find staring into one's eyes and holding eye contact with strangers kind of aggressive :)