It is not selling, it is called verification which anyone who have nothing to hide should do without having any problem regardless of online or offline work, you just saying this for the sake of it, tell me what is the difference between the kyc done online and offline? Your information is still in the hands of unknown people, besides people freely display their pic on Facebook and twitter which to me is more dangerous than some few information about name, age and address (this can be easily changed depending on your location)
You verify your identity all the time whenever you use any offline services, schools, hospitals, workplace etc, to me they appears same, but each to their opinion.
I think that it's not correct to compare KYC verification and identity verification on government institutions or workplace.
I'm actually talking about cases when people are looking for websites which pay for registration and verification - various online banks, crypto exchanges and etc. People give all their personal data with easy hand for few bucks. And there is no guarantee that they will sell your data to third party with bad intentions or it simply may be hacked and sold on dark web or websites like Raidforums. How likely that such thing with your data will happen in hospital for example.
Having your profile picture on social media is something dangerous because it's not secret information. But if you put whole your life into social media, it can make you into target of people with bad intentions. Especially if you live fancy.
Sorry if I went a bit off-topic, but I think it's still related with KYC on campaigns, even if question is already solved
.