Trolls of this nature simply don't have much going on in their head(s). They are controlled by simple appetites and have no thoughts beyond what is directly in front of them. About as smart as a turkey, but much more dangerous.
wild hunt troll - Trolls don't get any smarter after they die, if anything their time in Niflhel makes their tiny brains get stagnant and even slower than when they lived. These simple, stubborn wights are terrifying when their temper flares, but the trolls of the Wild Hunt are inadvertently dangerous even when calm.