Probably because were used to exhortation to good works being the sole province of god-botherers. That doesn't mean it's illegitimate. There are harms and benefits, and actions can and should be judged in the light of those harms and benefits, without being controlling and judgmental or lacking respect for others or a basically optimistic view of human potential or the possibility of rehabilitation.

Some things promote a sustainable civil society where people can pursue happiness on a reasonably level playing field; others don't. Some things most of us can agree are "wrong" without appealing to a theological construct like "sin". We can just look at the [un]happiness or physical / mental [un]healthiness or prosperity or penury that result from certain actions over time and identify unambiguous "wrongs" that we can agree to sanction or otherwise discourage, and unambiguous "rights" that we can agree to reward or otherwise encourage.

@mordant Yes, I think I am disaffected by him and all the so called Brights. I think his exhortation is cliched.