What is a straight wardrobe?

Popbitch says what people are asking this week:
Which bad boy rap megastar enjoys a public reputation as a womaniser but is secretly dating his bodyguard? He makes sure that he has a constant supply of beards, and also orders his stylist to make his wardrobe “as straight as possible”.
I’m actually asking what on earth is a straight wardrobe? I mean does that mean we can all walk around wearing G-Strings and sarongs like David Beckham? If so I’d rather wear a gay wardrobe thanks.
[via Popbitch]