Why on earth do people block free left?

Like, the concept is right there in the name free left. Not “optional left,” not “if-you-feel-like-it left,” but free. Now, not in this picture, but on my daily route, I have to take several lefts, and guess what? They’re all blocked. Every. Single. Time. So instead of smoothly turning, I get to stand there, waiting for the signal, watching someone in front of me stare blankly ahead, completely oblivious to the world, and according to traffic rules I have nothing to do with signal because I have to go to left. I just don’t get it. Are they allergic to efficiency? Do they enjoy unnecessary delays? Is there a secret society dedicated to ruining free lefts for everyone else? Because at this point, I wouldn’t be surprised.