Why? They're doing nothing wrong.
The Coinks system is used by lots of companies, and at no time will Coinks disclose your personal information without your consent. You do not provide a postal address, and you cannot be personally identified by any information that Coinks passes to a contributing company.
You can even opt out of receiving any marketing information. Your personal information isn't compromised in any way, and it might have been an idea to look into the system more closely before sounding off about one of the world's most famous brands. It's all there, on the Coinks website.