I don't really see what specific stances he's taking in the article. The thing he seems to do and do well (from reading the article) is have open conversations about everything and let the kids have open dialogue in a controlled fashion.
He indicated that he may not have issues with 17 year olds having a healthy active sexual life but he wasn't preaching that they definitely should be.
Yes ... part of my point is our collective social morality is formed by whether (and which ones and how many) people agree with a particular philosophy. It's reflected in research on the stages of moral development (see, e.g., Kohlberg).
One can't help but advocate for things they believe in by the way they live their life. (As a corollary, trying to have independent journalists is an impossible ideal; compare NY Times and Washington Post.) Trying to suggest he's not advocating his view of morality is silly, just as someone suggesting I don't advocate for mine would be, even should I attempt to be even-handed.
He indicated that he may not have issues with 17 year olds having a healthy active sexual life but he wasn't preaching that they definitely should be.