Correct me if I am wrong, but Facebook has the same policy and deletes suspiciously named accounts as well.

They technically have the same policy, but they don't seem to be proactive like Google is.

Also, Facebook doesn't use your name to find your friends, they use your friends list to suggest their friends might be yours as well.

Reason and method are both different.

In the beginning Facebook was far more restrictive in requiring a university email as well as a real name to sign up. If it had instead launched based on an open invitation system and not policed pseudonymous accounts then marketers and trolls would have ensured it remained an insignificant niche site.

If anything, real names were far more critical to Facebook's success than they might be to Google+

I have friends with the facebook names Hiphopopotomus, Joseph Stalin, and Professor X--and they've had these stupid names, that aren't their real names for a long long time--if there is a policy like this in place on FB they aren't really enforcing it.

Generally, I find that I often find that its only worthwhile to find someone on Facebook if I have their real name and common friends.

Do you have any statistics to back up your blanket assertion?

I find that searching for a specific person through a common friend is a tedious exercise of first going to that common friend's page, locating their friend list and then typing the specific person's first name to filter the list. This is not always fruitful as you would need to know that a specific person is in fact a friend of your suspected common friend, otherwise their profile would not come up in your filtered search.

However, if you type their name in the search input, Facebook will assist you by first finding friends of friends and then people of that name close to your home location.

Friending people as they come up tagged in common friend's activities is not search, it's affinity engagement, which is best achieved when you use your real name or the name most people know you by.