When one signs up for G+, their G+ profile (containing information about them) becomes public. It is easy to rush through the setup process, especially when one did not desire to go through it, and accidentally share more information than desired.
That's totally different, antsar. I'm 95% sure the motive for that was to simply grow the user base of G+ and try to get more people to know that the platform even exists.
That probably was the motive. But the side effect is that now people have public G+ profiles which they may not have wanted, sharing information about them (even as simple as their name and photo) that they would rather keep private.
Like the time they didn't feel the need to harass everyone into signing up for G+ any time one used an unrelated service?