The Left (which is intrinsically secular) always explains-away religious commitment and even martyrdom as being due to either social/ economic factors or mental illness.
So - for example - highly devout behaviour (e.g. people voluntarily giving large chunks of their time, effort and money to church projects) is explained in terms of them 'buying' various social support and benefits, and enjoying solidarity.
Or else it is explained in terms of brain-washing (from childhood). Or maybe in terms of religions terrorizing people by anything from fear of violence and murder; to fear of adverse gossip, shunning, expulsion.
In the event of religious aggression or war, the cause is not ascribed to the religion - but to something else such as oppression, exploitation, inequality, poverty, nationalism, economic self-interest, class conflicts, appropriation of resources... anything-but religion or religious difference.
Likewise martyrdom (voluntary self sacrifice for the faith) is explained in terms of the martyr either gaining tangible benefits such as status, power or money for relatives or the community (or penalties on these people for failing to martyr oneself); or more often in terms of mental deficiency such as being too dumb to recognize their own manipulation, or a frenzied and unrealistic enthusiasm or delirium (like a berserker rage or a violent drunk) or delusional 'fanaticism' where a psychiatrically sick person is operating on the basis of a pathological state such as delusions or hallucinations.
Some such non-religious reason is always ascribed for highly-motivated behaviour in the name of religion; because secular people simply cannot believe that actual religion is a real, powerful motivation - simply because they themselves do not share it.
For modern secular people, religions are merely a mixture of wishful-thinking fantasy, social solidarities and manipulations, and rationalized hatred; hence religion is just not the kind of thing which could motivate extreme commitment - and any evidence of apparent commitment therefore must really be due to... something else.
Yet religion is, in fact - and very obviously, potentially the most powerful of all human motivations.
And insofar as a society lacks religion - to that extent the society is demotivated.