The fact that Marmol gets the most called strikes of anyone in the majors (the inevitable result of having these pitches taken by batters) should not be over-emphasized. It is not the main reason for his insane K rate. Remember, Marmol has one of the highest (#9 out of all qualifying pitchers) swinging strike rates in the league, and there's a high correlation (R^2=.666) between swinging strike rate and K%. Meanwhile, the correlation between a pitcher's called strike rate and K rate is zero (R^2=.006). This shouldn't be surprising if you've been following along...after all, the swing rates against Marmol on 2 strike counts are still quite high and close to normal, showing that the vast majority of these called strikes come on counts where they can't result in an at-bat being over.
That said, it does explain why the K and BB rates of Marmol are so extreme, especially for a pitcher who actually does hit the strike zone not at a super infrequent rate. Batters when they find themselves ahead in the count, particularly in 2 ball counts (but starting in 1-0 counts), are opting to take pitches rather than to try and hit Marmol's elusive slider. The end result is that batters are putting less balls in play than they would otherwise and thus are having more opportunities to take walks or to strike out.