Indeed, the flight manuals for the Cessnas mentioned, refer to a specific use of controls while taxied in "strong" winds, and that would prevail over the preservation of the nose strut and propeller. Cessnas which spend that much time taxiing in strong winds, will just have higher maintenance, and risk of minor damage because of that properly executed use of the controls. That's taxiing, not "takeoff" or "landing", when the power comes up, it just became a takeoff, and things change.
The flight manuals do "recommend", or state "preferable" flaps setings, some being less than "full" for certain operations. "recommendations" or stated "preferences" from the aircraft manualfacturer are obviously wise to follow, though do not constitute an "approval" or the opposite of a prohibition. The strongest wording I have ever found in a Cessna flight manual with respect to large flap settings reads: "Flap deflections of 30 and 40 are not recommended at an time for takeoff" (1968 C 150). That's pretty clear, but it is not a prohibition of those settings, and certinly not of 20.
Some Cessnas I have flown do specify as much as 20 flap for takeoff (180, 182, 185, 206, 208) the 208 states that 20 is preferred. I concede that the 172RG recommends zero flap for takeoff.
I've never had problems with pitch authority taxiing Cessnas with zero flaps. I have nearly always had improved pitch authority taxiing with 10 to 15 flap, and that has certainly prevented damage while operating nosewheel Cessnas on rough ground.
Pilots are always advised to operate the aircraft in accordance with the stated terms of the flight manual. Pilots should never operate an aircraft so as to contravene "prohibited", "avoid", "use extreme caution when..." and similar such unmistakable wording. The use of the greatest permitted flap setting during any operation does not contradict any of these.
Squealing an aircraft on with reduced flap, and thus higher speed, so as to maintain that last amount of available rudder authority, is something I have never, and hope to never do. If that amount of rudder is needed to control a cross wind landing, I'll go elsewhere. My personal limit is that if I cannot accomplish a crosswind landing in a Cessna with good control at full flaps, I will go elsewhere. No problems yet.
Yes, Pilots should interpret and follow the wording of the flight manual in the way they feel most safe and comfortable. As a person who writes flight manual supplements for modified aircraft, I can truly say, that I appreciate pilots reading, and taking to heart, the words I have written for their benefit.