The fact is people do learn on their own and without someone to explain things, they will either take it literally or refuse to believe it literally.
You need a rebbe to guide you on that.
My question is that given that reality, I imagine even back in the time of the gemara there were people who would learn certain passages in wonderment.
I’m not getting what the question is (I don’t imagine it’s about lions), but I think that’s incorrect; at the time the Gemara was compiled, everything was transmitted orally.