AD&D 2e: Ranger's favored enemy ruling

From the AD&D 2e Player’s Handbook (p. 29):

In their roles as protectors of good, rangers tend to focus their efforts against some particular creature, usually one that marauds their homeland. Before advancing to 2nd level, every ranger must select a species enemy. Typical enemies include giants, orcs, lizard men, trolls, or ghouls; your DM has final approval on the choice. Thereafter, whenever the ranger encounters that enemy, he gains a +4 bonus to his attack rolls. This enmity can be concealed only with great difficulty, so the ranger suffers a -4 penalty on all encounter reactions with creatures of the hated type. Furthermore, the ranger will actively seek out this enemy in combat in preference to all other foes unless someone else presents a much greater danger.

As we’ve been using the 2e rules consistently for character creation and advancement, this applies to Gaertorin. Through a bit of research, though, I’m going to agree with what seems to be a large segment of DMs that restricting the favored enemy to a specific “species” is sometimes too narrow to be relevant in a given campaign. As such, for Gaertorin, the rule will apply to a broader “type” of enemy, which will allow him to appropriately favor “undead.” This should be a nice benefit to the party and is very much on theme for the character.