But can't even the anti-icing fluid itself create the stall speed to be lower. Because it is said that all contamination on the wings even small ones have effect on flight performance. So then when anti-icing fluid is supposed to be stuck on the wing. Won't the fluid itself also have an affect on flight performance?
I think you probably meant to say that contamination
raises the stall speed.
Assuming that was your intention, it is true that any form of contamination contributes to some extent to a change in the stalling characteristics of an aerofoil.
Ice to a
much greater extent than a soft smooth fluid.
2D