More tradition than anything.
Assuming you are cellaring properly, the colour of the bottle doesn't really matter. I guess if it's sitting on a store shelf for months a tint could make some difference, but I'm pretty sure that winemakers pick their bottles based on history and aesthetics.
I've also heard the explanation that because Bordeaux are big, powerful wines (relatively speaking for France), they come in a more masculine bottle (i.e. broad, square shoulder) while Pinot Noir is considered a more feminine wine and thus has a more feminine shape to the bottle (sloped shoulders, more slender shape overall).