Yes, this was done to protect the privacy of the certification holder and ensure that the person is truly who you are searching for. A name does not equal a person, it just equals a name and many people have the same name. Requiring that you know the person via something unique protects the integrity of the test and certification holder. This is quite standard in badging and certification systems.
It would be good to have the option to add a second email address to your profile. Some folks might have their profile registered on their work email address and/or might only share their work email address for business purposes. But as soon as they leave the organization their work email address is no longer valid.