Well... I mostly use my Amazon wish list to keep track of things that I will likely buy myself in the future. I don't really expect people to buy them for me. So I did not sign up for the site. However, it is a great idea and is something I am likely to make use of at some point. I just don't have a need at this moment.
Don't worry. I didn't feel attacked at all. I understand the need to get feedback from users (or non-user in my case) to improve things. And it was not even the concept that held me back... just lack of need at this time. Generally speaking, I'm not one to sign up for something until I actually plan to use it.
I suspect the site is one of those "Great idea! ...but I wouldn't actually use it" which is sad but maybe the honest truth.