Quite possibly. The modern library format contains a list of board types it runs on. If the Due (ARM) isn't listed then it won't be included in the list of libraries.

Quite possibly. The modern library format contains a list of board types it runs on (in library.properties). If the Due (SAM) isn't listed then it won't be included in the list of libraries.

For instance the SD library has:

name=SD
version=1.1.1
author=Arduino, SparkFun
maintainer=Arduino <[email protected]>
sentence=Enables reading and writing on SD cards. 
paragraph=Once an SD memory card is connected to the SPI interface of the Arduino or Genuino board you can create files and read/write on them. You can also move through directories on the SD card.
category=Data Storage
url=http://www.arduino.cc/en/Reference/SD
architectures=*

However the AVR specific SPI library has:

name=SPI
version=1.0
author=Arduino
maintainer=Arduino <[email protected]>
sentence=Enables the communication with devices that use the Serial Peripheral Interface (SPI) Bus.  
paragraph=SPI is a synchronous serial data protocol used by microcontrollers for communicating with one or more peripheral devices quickly over short distances. It uses three lines common to all devices (MISO, MOSI and SCK) and one specific for each device.
category=Communication
url=http://www.arduino.cc/en/Reference/SPI
architectures=avr

Note the last line of each - architectures=... - that defines what the library can work with. If your (unspecified) library doesn't have * or include sam in that parameter then there is no way that library will work with the Due.