I don’t think you have much training in either history or sociology. This is a hugely anachronistic statement. First of all, gender in the sociological context means the social performance of sex roles - everyone is always performing these all the time, and no sociologist would suggest that the majority of people “are conforming”, because gender is something that is socially produced and not something that you “are”. You’re reifying what is a long-studied and developed sociological concept for the past seventy years or so into an anachronistic formulation that doesn’t take account of the complexity of sociological work on gender for all of that time.
Second, since the performance of gender roles is always contingent, there are plenty of ways in which people have always historically adhered to them, or not, throughout history. The idea that “gender nonconforming people were historically persecuted and even today can be socially excluded and shamed” is extremely reductive and, largely, just not true. What’s your historical evidence for this? Were we flogging bluestockings in the village square? Publically shaming men who read novels?
Because it’s socially produced, “gender roles” varied constantly, across even contiguous eras, and is always highly inflected by class, race, locality, and even within the same person, may be performed in different ways from day to day. For every example in history you can find, there’ll be a counterexample right near by. Real people did not behave like a TV series or a book or even a historical chronicle. It would make more sense to say that the vast majority of people throughout history have been “gender non-conforming” apart from a very few.
If you truly approach the question of gender as a historian or a sociologist, you will find that variation, difference and change, the odd lumpy weirdnesses of history, are far more important (and interesting) than anachronistic ideas of “conformity”.
Imagine saying that “the vast majority of people throughout history conformed to their national identity”. What does that mean? What were nations? Was the idea of a nation state the same in 1500 as 1700 or 1900? Did they really? How could we tell? Whose ideas of national identity were those that they supposedly “conformed” to? What were their private thoughts? Did they really think “Englishness” was something innate? Did they believe in any of it or was it just a performance? Does it matter what monarch was on the throne? Were republicans “nationality non-conforming”? You can quickly see that the question doesn’t really make sense or look adequate to the complex ways in which society and social performance and ideas are intermeshed. Try it with other ideas like religious belief or identity categories like race, and you’ll soon come up against similar problems. In each case, you will find you dramatically misrepresent the past by trying to force it into reductive contemporary notions that don’t really fit.