No, this isn’t a cast iron thing. Using stainless pans, you can get nonstick effects that, in my experience, far outperform Teflon anyway. The process is called “spot seasoning.” I have cooked crispy, cheesy rice noodles with eggs with zero sticking.
I love my cast iron pans, but stainless is my daily go-to. Added bonus: use 100% copper wool to clean your stainless pan. The copper-coated wool at most grocery stores is problematic; you might get a few uses out of the coated garbage and then it starts shedding metal bits.
Teflon itself is perfectly safe. It’s far too large for your body to absorb.
But many of the byproducts involved in the production of teflon are much less safe.
In other words, if you already own a teflon pan, you’re fine. Keep using it. But if you’re considering buying a new pan, there are good reasons to avoid teflon.
Recent Veritasium video about “forever chemicals”.
It’s also important to note that Teflon (PTFE) is used in a multitude of stuff, and there’s no easy replacement. Got a 3D printer? The tube connecting the extruder motor to the hotend is probably PTFE.
The PTFE industry isn’t going to collapse just because we all switch to different cooking pans.
Lots of food machinery is Teflon coated, for example mozzarella machines
I have heard that coats are often covered with PTFE as well, as it makes the rain roll off rather than soak in