There is a difference between identifying with the things you buy, and the things you buy being your identity.
Identifying with Apple because you like x,y,z of their vision/products/services, etc. is one thing. The value of Apple as a public company having an effect on your identity is a completely different monster I think.
I wish I could put it into words why it feels so wrong, but hopefully somebody else here can explain the difference.
Can you actually tell me why identifying personally with the things we buy is a bad thing?