Another possible explanation
...newly released records show that Bush and Kerry had a virtually identical grade average at Yale University four decades ago.
In 1999, The New Yorker published a transcript indicating that Bush had received a cumulative score of 77 for his first three years at Yale and a roughly similar average under a non-numerical rating system during his senior year.
Kerry, who graduated two years before Bush, got a cumulative 76 for his four years, according to a transcript that Kerry sent to the Navy when he was applying for officer training school. He received four D's in his freshman year out of 10 courses, but improved his average in later years.
Keenly embarrassing, to be sure, for Mr. I'm-so-damn-much-smarter-than-that-smirking-Texas-chimp, but was keeping it hidden worth the price? Perhaps so, if he thought he could prevent this truly ghastly yearbook photo from seeing the light of day. Holy God, what a Goober!
(Hat tip: Althouse)