Yes. When someone who calls themselves Christian indulges in bad behavior, one can point to sacred writings and such to point out why they should change. When a secularist indulges in bad behavior, I honestly cannot think of any authoritative reason to give them as to why they ought to behave differently.
Exactly!
Some secularist are honest enough to say what they think:
"Why do we vent such visceral hatred on child murderers, or on thuggish vandals, when we should simply regard them as faulty units that need fixing or replacing? Presumably because mental constructs like blame and responsibility, indeed evil and good, are built into our brains by millennia of Darwinian evolution. Assigning blame and responsibility is an aspect of the useful fiction of intentional agents that we construct in our brains as a means of short-cutting a truer analysis of what is going on in the world in which we have to live.
My dangerous idea is that we shall eventually grow out of all this and even learn to laugh at it, just as we laugh at Basil Fawlty when he beats his car. But I fear it is unlikely that I shall ever reach that level of enlightenment."
(Richard Dawkins Writes About Human Responsibility In Light of Darwinian Evolution)
See my tagline.
It's really not that difficult to explain why anti-social behaviour is wrong in purely secular terms. Millions of parents do it every day to their children.
It's as simple as turning on the TV and watching news reports from areas of the world where law and order have broken down. How anyone could believe that anarchy (the ultimate result of unconfined bad behaviour) is preferable to the rule of law is beyond me.