The good news is that all you have to do is click the <Update your profile> button to remove it.
I checked out a few contacts and found that 25 percent of my contacts have their phone numbers exposed.
I'm fairly certain that when we registered for Google Plus we didn't notice that the default setting was to expose our phone number.
You have been warned.
This is an example of how not to design a registration page.
Registration pages should present users with the option to "Opt In", i.e., users should have to take action to click a checkbox, rather than have to take action to "Opt Out" of sharing personal information.