Yes, people with diabetes can eat honey graham crackers. The amount of honey or sugar in most brands of graham crackers (other than chocolate covered) is not considered significant.
Three graham crackers measuring 2 1/2 inches square is equal to one starch exchange. So if you would like, you can eat three graham crackers instead of one slice of bread. Remember, however, to reduce the starch exchanges in your diabetic eating plan when you eat graham crackers.