Complex sentence: The Source-Red Hood and the Outlaws Preview Tamaraneans in the DCNU are said to have short memories and to care little about Earth, seeing humans as little more than sensory experiences; this apparently is why Starfire has forgotten all of the Teen Titans.
Split into simpler sentences: The Source-Red Hood and the Outlaws Preview Tamaraneans in the DCNU are said to have very short term memory. Due to not caring much about Earth, they see humans as little more than sights and smells; this is given as the reason for Starfire having forgotten all of the Teen Titans.