I agree, but in case of an extremely low Re along with a rather thin flat plate wing, the air molecules "reshapes" the plate into a cambered airfoil (at a positive AOA).
As the Re gets smaller, the required thickness gets smaller, but there are also drawbacks for being too thin e.g., the max thickness point has to move forward and its distribution along the airfoil becomes critical as well.
If you want an airfoil for an extremely low Re that also has a wide speed range, the job gets rather tricky.
I think designing really good airfoils for extremely low Re is one of the most difficult challenges in the model aerodynamics.
adam_one,
I understand how the 'reshaping' can happen, but it is not unique to airfoils that are thin or flat, and it is not the entire explanation of the performance characteristics of thin airfoils.
Low Re airfoils are tricky, mostly because the body of knowledge we would like to take advantage of is all aimed at higher Re airfoils, and hence often not applicable. Beyond that, it is tricky to optimize an airfoil for any set of operating conditions, whether it is low Re, high Mach number, etc.
banktoturn