There are two different issues: (a) when you walk, drive or run, your experience the flat nature of the Earth. (b) whether experience is veridical or whether whatever experience in the world mirrors the reality of that world?
There is no need to be critical of those who believe in the flat earth theory, because their experiential evidence supports their theory. How to change such flat Earthers? Well, you need to set up an experiment involving them. Probably take them to space station, then they can get convinced. Otherwise, it is an issue of believing authorities.
There is nothing wrong in believing some scientist. However, when one enters in a dispute with scientists, one should become a scientist himself.