In practice, English-speaking countries don't use "theism" to refer to the belief in multiple gods. We'd call that polytheism. That's because monotheism is the religious norm in such countries. And those are the countries Medium is mainly talking to.
Your complaint about my writing style is asinine, coming as it does from a non-native speaker of English. I don't take that complaint seriously, and no that doesn't commit me to saying my writing is immune from criticism. There's a big difference between criticizing style and criticizing substance.
If you think Jews and Christians interpret the Bible only as making claims that should be interpreted literally, you have an awful lot of studying still to do. In particular, the naive, literalistic, dogmatic interpretations were dealt a severe blow by the rise of the critical-historical approach to the Bible a few centuries ago. The Scientific Revolution made historians realize they could use their powers of critical thinking and doubt certain religious dogmas. Much of Genesis was a rewrite of older, Sumerian stories.
And it's very foolish to treat a myth like you'd treat a scientific theory. To literalize a myth is to trivialize it. Myths are stories that have the power of great fictions.
It's telling that you didn't even bother to look up "Dunning-Kruger effect" just by googling it. You do realize you're allowed to learn new things, right?