This is just silly. Most iPhones with air drop turned on for everyone are probably like that because the user couldn't make it work otherwise. It's not an expression of the user's desire to, or comfort with, receiving files from strangers. And it's not an invitation to send any kind of photo, let alone an obscene one. The vast, vast, vast, majority (statistically indistinguishable from "all") of the population does not want unsolicited dick pics. Having airdrop turned on is no more an invitation to receive them than having a mailbox is.