This subjective kind of programme is authored, and is strongly skewed towards a certain viewpoint. They tend to be films that tackle issues.
The filmmaker might be the main the protagonist making their presence felt whether they are in front or behind the camera. It is an approach often favoured by independent filmmakers.
Or the point of view documentary can be hosted by someone who immerses us in their world, has particular take on a subject, or a campaign agenda, such as:
Jamie’s School Dinners (Ch4)
Jamie’s Kitchen (Ch4)