Sheez, how many times ... gender is your sexual identity, the sex your head feels you are. Sex is the bits and bobs of the body.
To say you are cisgendered means that your head's notion of your sex matches that of your body. Transgendered means that your head's notion of your sex is different to that of your body.
It's a plain statement of facts, not a oneupmanship.
Furthermore, it would be inaccurate to call a transgendered person gay if they have the body if a man and the mind of a woman, but are sexually attracted to men. That is actually 'straight', because the body is not the identity, the consciousness (i.e. the mind) is the identity. There are people on here who have the mind of a man and the body of a woman and are sexually attracted to men. That makes them gay, even if the book cover does not match the content.
I'd go as far as to suggest to you that it is not the people who claim to be transgendered who are being superior, but people like you who demand your (mis)understanding become the norm, and affect to have everybody live according to a set of parameters just so you can understand. You are basically decrying them for expecting what the rest of us want, i.e. an uncontested space in the world where their specific peculiarities are just as uncontested as your peculiarities or my peculiarities.
I do appreciate that you are asking the question, but I don't appreciate the high and mighty tone it is delivered in. You are young and living in a generation where certain things are much more acceptable. For instance, how would you react if someone told you that you could not adopt children or father your own because you don't have a great set of milk jugs and you like taking it up the ass? It would be ridiculous. So is your stance.
We cannot expect to be granted an uncontested space in the world if we cannot grant the same grace to others.