Since 20 years nobody has being using rectangular traces anywhere. No, I'm not a professional in this area, but even I know this and have used this knowledge for my own designs (don't worry, no motherboards ;-P ).
For those who don't know, the whole point to curved/curled traces is to ensure all the signals arrive at their destination at the same time. If things get out of sync, that's bad.
If anything, their routing software needs some critical updates. :-)
