The plants listed are recommended as the resistant plants, no plant can be really deer or rabbit-proof! Garden plants are often browsed by hungry animals if there is little or no natural greenery to eat in the surrounding area. But even if there is fresh young spring greenery around, especially young rabbits and also young deer will try anything, this might be the learning process of tasting plants around them.
Also there are regional differences what animals like or dislike or their taste can change in time...But generally we can say that plants with a strong odor, fuzzy or leathery leaves, needles or thorns are more resistant than others. Native plants from drier habitats are also more resistant than others.
It is always best to combine different strategies - plant "deer and rabbit resistant" plants, use fencing or deer & rabbit repellent (liquid fence, odor fence).