Investigation Discovery airs a laudable one-hour documentary on May 20 titled “Children of Promise: The Legacy of Robert F. Kennedy.” The hour explores Kennedy’s Children’s Action Corps in Massachusetts, an organization founded in his honor that’s committed to “successfully rehabilitating and mentoring children of crime, violence and neglect.”

Given its laudable aims, it’s only too bad that “Children of Promise” — which focuses on three case studies of kids helped by the center — isn’t more interesting. Yes, I admit to being part of the problem in this case, but as produced, this tastes an awful lot like broccoli TV — good for you, but not much flavor.

In a way, the Oprah Winfrey Network has experienced the same problem, which explains its initial growing pains. Yes, there’s room for stories of uplift on television, but frankly, that market is pretty well served by “Today” show segments and newsmagazine features. It’s hard to sustain an entire program — much less a series — on those principles, unless it’s extraordinarily compelling and solidly produced.

In essence, “Children of Promise” plays like a public-service ad for a worthy cause, but a PSA nevertheless. That’s the same hurdle, by the way, that OWN has to clear — and danced around with its recent executive shift.

While it’s easy to applaud ID for putting on this Mandy Patankin-narrated special (which is produced by NBC’s Peacock Prods.), it’s a little harder to recommend that anybody sit through it.