Torsocks works by DYLD injection. As of 10.11 this kind of modification will be disallowed by a new feature called “System Integrity Protection”. It is also known as “Rootless”. The feature prevents both modifications to your system files, and to system processes whilst they are running (even if you enter your password for administrator access).
So on a normally configured Mac, torsocks cannot run with binaries in the /usr/* directory.
You can actually turn System Integrity Protection off. To do so, you must reboot into recovery mode (it is not meant as an operation a regular user would do).
From terminal in recovery mode run: csrutil disable;