They have no reasoning, push them and they will resort to criticizing the crease or device thickness, but won't be able to come up with a reason why this isn't a solution for *some* consumers. No one is trying to say foldables will replace the entire smartphone market, but many just put blinders on and because there is no use for themselves and try to extrapolate that to the rest of the world.
Besides the incredibly obvious point that even my 6 year old can see, that a folding phone fits better into my pocket than an iPad Mini does, it's really difficult to reason with some people that can't grasp something as incredibly basic as this. Note: this is different than someone saying they don't like the crease, or that they are worried about durability, which are legitimate concerns. Not MY concerns, but still legitimate concerns that consumers are entitled to.