The catholic church believed that theatrical performances were blasphemous and places of debauchery which led people to sin. This would be the closest answer possible since you didn't provide possible answers to choose from.
"like an arrow presently to his home in the green world beneath"
<u>The answer is 1: He thinks the fighting is foolish and wasteful.</u>
The narrator's view on the scene is not pleasant at all, Grendel finds himself in the middle of chaos, in the middle of all the battle's wastefulness and dead bodies of animals and men, and he can't help to see it as confusing and frightening and to feel "sick". All of this reveals that Grendel thinks the fighting is foolish and wasteful.