The only Warriors with true shooting percentages below 50% are Biedrins, Ezeli, Tyler (26 total minutes), Jefferson, Green and Bazemore (26 total minutes). Other than the two scrubs, none have a usage rate higher than 14.6%.
Monta's usage rate is 28.2%. The only player in the NBA with a higher usage rate and a lower true shooting percentage is DeMarcus Cousins (aka Monta writ large).
This is why Monta is addition by subtraction. Dude simply takes too many hard shots, resulting in an extremely high usage for such poor efficiency.