So I would take several opposing concepts from scripture. Light & Dark or Visible & Invisible, for example.
And I would use them to make a point which encourages free associative type thinking. This differs from Science in that its not objectively factual...and my critics may charge me with being dishonest through making stuff up.
My response is that what they teach only reinforces doubt. I market certainty in Jesus Christ.
They charge me with "making God up". I'm starting to think that it is useless to attempt to disprove this notion.
I think a few concepts are being mixed up here and in other posts, especially the idea of "relativist". The people you are calling "relativist" are really either just stating how your conclusion can't really be drawn from inter-subjectively accessible evidence. There's a difference between that and relativism.
Relativism to me would me something along the lines of Ganesh is literally real to Hindus while Thor is literally real to Scandinavians and so on, i.e. that multiple mutually contradictory theological metaphysical views are simultaneously true each within their culture. It could also mean they are each of equal cultural value.
However people here aren't really discussing either of those possibilities. They're simply saying how for the external observer there's nothing outside of personal testimony for each of these gods.
Imagine I lived on an island and had scanned the horizon never seeing another landmass multiple times. One day I meet some people who each say they have in fact sailed out there. One says he saw another island, another saw a monster, another saw a floating city and so on. They all have nothing to corroborate this. It's not relativism to say "Sorry guys, I can't accept any of this".
Even if we imagine you are correct none of this would be relativism. It would just be not believing due to the lack of sufficiently convincing evidence.
Beyond this I would say two things:
(a) As far as I can see from commentaries on the original Hebrew, the Bible isn't really monotheistic. Yahweh says he will punish the gods of Egypt, the Psalms say he will punish others in the divine council, even calling these others "gods".
(b) The phrase "marketing certainty in Jesus Christ" is an interesting example of cultural differences. Again my main exposure to religion is Irish Catholicism to which phrases like this would be kind of alien. First of all because being certain in your faith is not as stressed here, in fact doubt is a big part of being Catholic here, it's supposed to be present as part of faith. Also the use of words like "marketing" would be seen as inappropriate as such since it applies mundane concepts to the transcendent. Not that this makes Irish Catholicism likely in any sense just that I want to emphasise that confining the debate to:
19th Century Science inspired materialist Atheism vs Post-Enlightenment American Evangelical Protestantismcreates a very distorted view of both the religious and scientific.