Complex sentence: The Datasette (cassette) port and RF port were omitted from the SX-64 because it has a built-in disk drive and monitor, and therefore Commodore did not perceive a need for a tape drive or television connector.
Split into simpler sentences: The Datasette (cassette) port and RF port were omitted from the SX-64. Because it has a built-in disk drive and monitor, Commodore did not perceive a need for a tape drive or television connector.