People orientation manifests itself in a number of different ways in agile processes. It leads to different effects, not all of them are consistent.
One of the key elements is that of accepting the process rather than the imposition of a process. Often software processes are imposed by management figures. As such they are often resisted, particularly when the management figures have had a significant amount of time away from active development. Accepting a process requires commitment, and as such needs the active involvement of all the team.
This ends up with the interesting result that only the developers themselves can choose to follow an adaptive process. This is particularly true for XP, which requires a lot of discipline to execute. Crystal considers itself as a less disciplined approach that's appropriate for a wider audience.
Another point is that the developers must be able to make all technical decisions. XP gets to the heart of this where in its planning process it states that only developers may make estimates on how much time it will take to do some work.
Such technical leadership is a big shift for many people in management positions. Such an approach requires a sharing of responsibility where developers and management have an equal place in the leadership of the project. Notice that I say equal. Management still plays a role, but recognizes the expertise of developers.
An important reason for this is the rate of change of technology in our industry. After a few years technical knowledge becomes obsolete. This half life of technical skills is without parallel in any other industry. Even technical people have to recognize that entering management means their technical skills will wither rapidly. Ex-developers need to recognize that their technical skills will rapidly disappear and they need to trust and rely on current developers.