Although net fishing requires placing the net in a direction where the player character can see, this restriction is absent in rod fishing.
While reality proves it's possible to
cast a line backwards (see this
youtube short), the technique seems atypical and doesn't correspond to the flavor text:
You sit down, spit in the water and start to angle, dreaming of a huge catch.Nor is it immersive for the player to remain facing away for the entire angling session.