I consider it a fair trade. I hand over my contacts and you tell me with high-confidence who the other person on the other end is.
Especially as part of a commercial transaction to a for-profit company?
"Hey, Bob! I'm going to give some company your name, phone number, occupation, and whatever else I know about you stored in my contact list in exchange for a beer. Is that OK?"
Once you give your info away it is not "your" info anymore. It is info about you, but you do not own it.
Is it rude? sure, but not illegal.
Depends on the jurisdiction. Under the GDPR this might very well be illegal, though obviously enforcement of it is significantly lacking so it's unlikely to ever actually be tested in court.
okay.