support why i picked "the struggle between two opposing forces"

I'm not too sure what you mean here. There is definitely a struggle between the pirates and the explorers. This is an adventure tale. It is escape fiction although pretty good escape fiction. The pirates are "bad", although much more interesting, and the intrepid treasure seekers are "good" (more or less). The struggle becomes simple to follow and it's a fun read too! If you have something more specific in mind, just let me know.