There are tons of people who called Quora annoying for doing the same thing. They also have a tendency to go around in public talking about how they won't use it because it's so annoying. Annoying or not though, it gets people to sign up and many of those same people who claimed to not want to join because of it being annoying end up on the site. Maybe it is annoying but the concept works.
Good thing I am not so insecure about my ideas that I need others to give me validation for them.
I can imagine though that the kind of person who goes to networking events on eventbrite, who starts talking about his 'great and orignal' 'idea' to create an app where people can take pictures of food in restaurants and then let others search these pictures to see whats for dinner around them, does need this validation. (I have actually been to numerous events where more than one person at a single event had this 'idea'. )
I think when your idea is crap, you secretly know it, but after quitting your job and investing all of your savings, it becomes really hard to cut your losses.
Now I don't think having an idea is the same as executing it well, but I could imagine people being hesitant.
Oh and because of the annoying landing page I vow to never to use your site, nice try.