The article never mentions religion, while religions everywhere present themselves as a beacon of morality.
People believe that morality is declining. Is it? Societies keep (or at least leave) reasonably good records of extremely immoral behaviour such as slaughter and conquest, slavery and subjugation or murder and rape, and careful analyses of those historical records strongly suggest that these objective indicators of immorality have decreased significantly over the last few centuries.
This is a very naive view of morality in a country conquered by religion. Ask a christian if he believes that this is morally fine that his neighbour is gay.
Was conquering north america moral? How many native indian did Davy Crockett murder? He is celebrated as a hero even by Disney, is it moral?
How can you qualify all of this as science material?
People clearly perceive moral decline, but to what do they attribute it? There are two possibilities. The average morality of a population may decline between two points in time (T1 and T2) because (1) individuals who are moral at T1 are less moral when they reach T2 (a phenomenon we refer to as ‘personal change’), and/or (2) older people who were alive at T1 but who died before T2 are more moral than younger people who were alive at T2 but who were not yet born (or who were not yet adults and therefore not sampled) at T1 (a phenomenon we refer to as ‘interpersonal replacement’).
Oh, that's why, there is T2 and T1, so We can do T2 minus T1. Sure.
The orthodox church in Russia has blessed the weapons of the russian soldiers, so by definition this war is moral. Do your T2 minus T1 in Russia and ask the russian citizen if Russia acts according to morality right now, you will get fantastic results! I'm not sure that your results would have any scientific value though. I'm very disappointed by Nature.