To to back to the OP, even though people are taught things at school, that is no guarantee that they will retain them. I teach adults, and at least half of them claim not to know what a verb is, or never to have heard of the English Civil War, or not to have come across Moses (or any other piece of information which might reasonably count as general knowledge). Studies show that people listening to a lecture have forgotten 90% of it within ten minutes, so it is not terribly surprising that out of all the things they learn at school, they forget quite a lot of them. However well they are taught! And it certainly does undermine the credibility of the 'indoctrination' argument if so few people who've apparently had Christianity rammed down their throats have retained so little of it.
The people who noticed the similarities between the story of Noah and other Ancient Near Eastern flood narratives were biblical scholars studying the sources of the Bible. I'm not going to be swept off my feet with amazement by being told something I know very well already. I'm happy to have a talk about some of the hard bits in the Bible, because I'm committed to grappling with the Bible as a whole. And I'm committed to using the best scholarly tools available for doing so. Regarding Noah, I would say that the consensus of scholarly opinion is that this story is part of the section of Genesis which takes place in primeval time; the stories are myths not history; and the most relevant question is not, 'did they happen?' (the answer is no) but 'what do they mean?'. Myths have all sorts of horrible things happening in them Zeus eating his own children for example, and we need to understand what meanings these stories have what they tell us about the people that originally told them, and the people that wrote them down (separated as they were by some centuries), and what they might have to say to us today.
And, of course, the story of Noah is a terrible one. But it ends with God making a covenant that he will never destroy life in the same way again. I would say, briefly, that it needs to be seen in symbolic terms as one of a series of stories in Genesis about the relationship of humanity and God, each of which emphasises God's covenant relationship with humanity. So, although it is a difficult story, I would want to engage with the difficulty, and this is true for all the difficult bits of the Bible.
And, just for the record, I have read the Bible cover to cover.