If you google Landmark, what comes up is "Landmark Education". Most forget that second tag. But it is this that enables Landmark to worm its way into the heart of conventional thinking and organizations. And when you have an array of "graduates" from your courses, respectability looks promising.
Universities, for example, are keen on promoting personal self-development plans for their students to equip them supposedly for the workplace. This is precisely the opening that Landmark seeks to insert its programs.
Even law firms without their full knowledge are supporting Landmark with lawyers earning continuing legal education points for taking their courses. But remember, Landmark IS NOT ACCREDITED BY ANY SIGNIFICANT EDUCATIONAL SPONSOR.
Because Landmark uses a variety of volunteers who work with them and their own organizations it eases the process of introducing Landmark techniques into the legitimate workplace.
Added to which we see how graduates can overstep the line when they start to suggest to clients (I know lawyers who have attempted to sign up clients) or patients (as did the doctor in the French documentary). This becomes unethical.