Beowulf, poem to movie

The poem is all about honor and dignity, but the movie is all about sex. Beowulf's curse and the explaination of the dragon is sex with Grendel's Mother. In the poem it is because someone stole the dragon's cup. In the poem Grendel can't harm Hrothgar because he is protected by God, but in the movie it is because he is Grendel's father. So they changed most unexplained parts of the poem with "sexcuses"