Of course, it goes without saying that things were always messy. There were Israelites who urged a strict rejection of all gods in favour of YHWH. This was, I would argue, the fruit of what Lonergan calls "intellectual conversion," i.e. the foundational apprehension that knowing is not like looking, that reality is not what is out there to be perceived but rather what is to be inferred from what can be perceived. Thus the rejection of images flowed from and indeed aimed to concretely communicate an epistemic insight into the very nature of insight. Of course, this apprehension took place at the level of the time, and the level of the time was the Iron Age Levant. This apprehension could only proceed as far as that level permitted, but it advanced that level. Lonergan defines genius as the intellect operating fully at the level of its time, thus advancing the level for future generations to build upon. In that sense, the Israelite prophets perhaps are best conceptualized as geniuses who apprehended the nature of human knowing as clearly as their time permitted. They transcended the common sense of the time--what was affirmed spontaneously and without reflection--to produce insights into the nature of reality so profound that we still read their words three thousand years later. (Note that this does not obviate divine activity, for there is plenty of room for a doctrine of grace as that which gifts the intellect with the capacity to undertake this work, nor does it obviate a doctrine of revelation but rather specifies more precisely the concrete human side thereof. But such concerns are those of the systematic theologian, something I am not). But precisely insofar as such rejection of the gods in favour of YHWH demands that one was operating fully at the level of one's time the vast majority of Israelites found that difficult to achieve. It is not surprising but rather quite predictable that they would continue to function at the common sense level of the time, bowing before that which could be seen as they could not conceive of reality as something apprehended not by the senses but rather by the intellect. Similarly, there continue to be followers of Abrahamic religions who remain unable to distinguish between perception and reality.
Perhaps the reason that this qualitative difference between "God" and "the gods" eludes many today is because they have not themselves apprehended that knowing is not like looking. Supposing that only that which can be perceived can be affirmed, their inner life has more in common with ancient paganism than the level of our own time. Indeed, those who state that they differ from polytheists only quantitatively explicitly affirm that the pattern of their thought is essentially that of the Iron Age. Put otherwise, there can be a reasonable argument for atheism, but one that is unable or unwilling to engage with what other persons actually believe to be the case hardly qualifies as reasonable. If one has rejected only quantitative distinctions between "the gods" and not attended to the qualitative distinction between "the gods" and "God," then one's atheism is inchoate at best.