Value or Bluff raise

In applications of NLHE, the author consistently includes combo draws in the value part of raising range on the flop. This just seems wrong. He says that the required strength of a value raise should is around 90% equity in one chapter and then goes on to putting draws with equity barely close to 50% in the value raising range. For example, in one hand example about defending against a flop bet, with the flop being Kd9s7s, the author lists QJs and QTs as value raises when these two draws have equity < 50% here. Should I just ignore these parts and instead just include them in my bluff raises? Why is the author doing this?