See here Points Per Game Allowed is a NEGATIVE category. Hence, red colour was chosen. Red is a negative colour. You know how when you drive a car and you see a red light you must STOP. So this category Mavs also need to work on STOPPING.
And Points Per Game Scored, on the other hand, is a POSITIVE category. Hence, blue colour was chosen. This is a category that we as fans and supporters and contributors want to grow, encourage and even identify with. And that is the colour that Dallas Mavericks also happen to wear most of the time.
Those are details. And those are very, very little things. But those things matter!
It is, after all, details that also win championships.