Complex sentence: One such factor was Manuel Alfonso, an author who sought to idealize the Jibaro through a biased racial perspective, and Popular Democratic Party of Puerto Rico, that sought to idealize them for political gain.
Split into simpler sentences: One such factor was Manuel Alfonso, an author who sought to idealize the Jibaro through a biased racial perspective. The other major factor was Popular Democratic Party of Puerto Rico, who sought to idealize the Jibaro for political gain.