The weariness of a society who do not let itself delude more longer by an ideology. For the "d'" which means "de", it's for express a quantity. In this way, it expresses the variety of an ideology. Anyway, you've also to demonstrate and to enumerate in French what you're talking about. So, you could say too : "qui ne se laisse plus bercer par une idélogie (n'importe laquelle)", or : "d'une ideologie". But, implicity, in reference with the verb "bercer", the "de" could be read into the following meaning : "bercer de doux rêves idéologiques".