Could you help me understand why you find that scary? It's not giving him any information which wasn't previously available to him. I think you're concerned that people are overlooking his screen, and you'd rather he explicitly choose everything that pops up when you call? Do you think he wouldn't have included any identifying information about you?
As a user, I'd rather have not only a name but also a picture of a person pop up when they call me, and I'd rather it happen with as little work as possible on my part.
(disclaimer: I work for Google, although I had nothing to do with how this works)
OP desired to keep his Google associated email and non Google associated phone number separate, and behaved as such. That's a very reasonable thing to want and do.
But Google used OP's friend's phone, bought from them, to surreptitiously acquire the connection between his email address and phone number.
That was against OP's desire, and his friend never explicitly agreed to provide that information. I fully understand why he would be upset.
I think everyone is misunderstanding the complaint. Google does not link phone numbers to accounts based on being added to he same contact. The poster is just complaining that it shows the photo from his Google profile (attached the the email his friend already knows) and shows that when he calls from his phone number (that his friend also already knows and added to the same contact).
Oh, yes, I missed a sentence: "Which I guess means that Google now also connected that phone number to the mail address/Google account." So I suppose freeflight's concern is what information the friend gave to Google, not what Google gave to the friend or what the friend's phone is displaying to onlookers.
This is how cloud services work. Google stores the friend's contact data, which has a contact with both freeflight's phone number and email address.
What is it you fear that Google is doing with this information? And what would it take for you to be comfortable?
Not OP, but: it would take for cloud services not to work this way. Regardless of whether Google is going to do anything with this data, the fact that tech-literate people aren't able to prevent just this from happening even when trying really hard makes one wonder how any one could avoid anything.
As a user, I'd rather have not only a name but also a picture of a person pop up when they call me, and I'd rather it happen with as little work as possible on my part.
(disclaimer: I work for Google, although I had nothing to do with how this works)