Sans scrupule: transsexuality or transsexualism

I am confused. Confused because a word is bugging me, a word not used in my native language, but used frequently in the English and Nordic languages when mentioning the condition extreme gender dysphoria. In my opinion that condition is called transsexuality, but more often I read about transsexualism. This word is bugging me because it ends with -ism. In my perception an -ism is about a collection of ideas about a certain theme, like socialism is about politics and shaping society. Though indeed there are diseases and condition ending in -ism, but I don’t suffer from a disease, neither is this a condition which defines me as a transsexualist. The word transsexualist isn’t used while the -ist is used with any -ism I am aware of. My transsexuality is a diagnosis, put upon me from outside as to name a certain condition, it doesn’t define me nor my ideas about myself, the world or anything else.
I have less problem with the words transgenderism and transgenderist, which are becoming more and more common for those people whose gender identity is neither male or female or a bit of both and this idea shapes how they present themself, and often too how they perceive gender in general. I am not a transgenderist, so I don’t own that term and cannot deny people to use that -ism. Having an -ism put upon me is what bothers me, of course I can understand opposition against the word transsexuality because it contains the word sexuality, and of course it has nothing to do with sexuality. In my opinion the word sexualism doesn’t fix that, not only because of the interchangeability but mostly because the term transsexual is still there to hint it to be about sexuality falsely connotating with homosexual and heterosexual.
I do not identify myself as a transsexual, of course I do use the term as I do use transsexuality, but it isn’t a selfdefining aspect of my identity. I use it for clarification and to have other people familiar with that term understand my situation (and of course to find my blog). It is easier for humans to name something, it makes it possible to connect with one an other about something. As I do here on my blog. When I first read about gender dysphoria and transsexuality, especially the word transsexuality felt awkward to me, mostly because it was connected to older transwomen with whom I couldn’t identify. I’ve let go of that uncomfortable feeling with the word simply by not identifying myself as a transsexual, though not denying the condition. In my opinion the medical society owns the term because it is for them necessary to name a condition and aid people with that condition.
In the discourse about transsexualism it is possible to defy someones claim on owning it by self diagnosis. This makes it possible for transsexualism to be something which isn’t fixed, but something with which one identifies and does shape a person’s identity and ideas about especially gender. Transsexuality isn’t an -ism and offers less space to identify with because of it’s medical origin, and it being owned by the medical society and not by individuals whom believe to be extremely gender dysphoric. In my opinion a medical practitioner is wrong to use the word transsexualism, becuase a patient simply isn’t a transsexualist nor transsexualistic person. So in my opinion it is simply illogical to use the word transsexualism, but of course I cannot force anyone to stop using it, but it would be nice to have some coherence about the language we use, within the transgender community and within the discourse about extreme gender dysphoria.
It might just be an issue of how I experience transsexualism in how I use -ism in my language. I have only one -ism which shapes partly shape how I think about myself and the world and that’s individualism, an individualism which I shape and no outside ideas about it are able to own my individualism becuase I am an individual with an individual mind. Being an individualist doesn’t leave any space for other -ism’s but makes it possible for my to grab ideas here and there and be open to any idea, without losing my individuality.