You're just restating what it means to be "brighter". To remove the surprise you have to find a mundane explanation for the difference in albedo.
The surprise should be removed by the fact that we've known each body's albedo for decades. I was surprised that the a space scientist working on DSCOVR wasn't aware of the differences in albedo, or was aware but hadn't actually pictured the difference in his mind. It just seems odd for someone in his position to be surprised by this.