I think you're being much too black-and-white here. The majority of us hate our leaders and their ideals, but we don't rise up and overthrow the centuries old system we have in place (European countries, obviously - America hasn't been wiping its own arse for that long). A nation of pacifists aren't pacifists to their very core, which is why you and GC are, in my opinion, arguing unfairly. It's dishonest to argue about a perfect planet-of-hats people on your side, and then throw out valid observations from the significantly more complex real world.
That is what we are talking about, you can change the rules around so that people are more moderate, but that was not what we are talking about. The complexity of the real-world in any case generally illusory, created by people taking into account actually irrelevant details and giving them a primacy they don't deserve and treating arbitrary distinctions as facts.
The majority of people do not hate their leaders and their ideals, if they do then it is only a slim majority that does so. If the overwhelming majority of the people hate their leaders and their ideals, then the rulers will fall. Or else how do rebellions and revolutions actually happen?
Technically caste is simply a system for creating subvariants of creatures which Toady only really uses for biological gender but which is a powerful tool for modders creating less standard species and creatures. Not that thats particularly relevant here, but its a distinction.
I do feel that GC is right here and that the proposed state in which a tiny minority relying on the obedience of a huge population that is diametrically opposed to everything they do without any support or similarity in goals is fundamentally doomed. That caste of supermen might be able to take over the system from the top and rule it for a short while, but no government can stand when literally every aspect of the system including their own enforcers hate them and their ideals
Caste is a flawed stand-in used by modders to create subvarients of creatures, because they are forced to do it that way. It is deeply flawed because you cannot make them hereditary, because the system was built for the sake of having male and female, it was not built to support different social orders.
From the accounts I read from the one hundred years wars, they really don't give a damn about who is in power. When the power in a city changes, this is the opportunity for a carnival, and the population likes that since it is customary for the new lord to distribute gifts to its new population.
They have absolutely no lasting loyalty. This is a foreign concept that do not even occur to them (from my readings)
Edit : That said, pre-roman or early middle age had a different approach, since the nobles were basically peasants with weapons, taken from the population itself (don't quote me on that).
If people had no lasting loyalty, then how was it possible for kingdoms and political arrangements to persist for hundreds of years, basically you are talking nonsense to a frightening degree. The lords ruled because people had loyalty to them, or at least to their office and were prepared to die for them as a result. 'Natural selection' would quickly eliminate any regime that did not rest upon any kind of 'lasting loyalty', any rival regime that inspired such loyalty would sweep it away with ease.
In effect, the situation works no differently from a modern dictatorship. People celebrated when the Americans overthrow Saddam Hussain, but as we know in hindsight this in no way implied that people in general were supportive of the American puppet government. The 100 years war is similar, it is a war of religion and both sides contain a lot of hidden adherents to the other side's religion. These people will celebrate when the other side wins, not because they have no 'lasting loyalty' but because they have such loyalty to their religion and support the overthrow of the dictatorship of their own side's religion over them.
Maybe we can discuss about differences like that in DF societies, rather than about 20th century ideologies which are a bit out of place in a medieval setting. Variables like "how does someone becomes noble", "what are the perks and responsabilities of nobles" and "how the population views them", stuff like that
It is the same reality, the same human nature and in many cases broadly similar ideas and institutions. Historical eras are categories made up by historians, they don't really exist as hard facts and so hard statements as you are making cannot legitimately be made. In any case, the DF world is currently almost as alien to medieval society as it is to modern society, but we are more familiar with modern society's terms so we use those terms to understand DF society rather than medieval one's.
I mean as far as I know, medieval/renaissance government types are of three kinds ; city state republics, where the city governance is independant, feudalism where the landowners are the vassals of bigger landowners and have their legator inherit their lands, and imperial where one man controls all and local governors are just his representatives and are designed and removed according to the monarch. We could add to this a tribal/pre roman system where the leaders are elected by the community, and I believe we have all possible government systems of that time.
The details could be procedurially generated (ex ; you need to be a magician to access nobility and non-magic nobles are automatically replaced as soon as a magic user is available, or your father need to has been a noble for you to be a noble etc)
Just some thoughts
None of those concepts are relevant because DF society is not a medieval one.