This is now an outdated view. Trans (which includes transvestites/crossdressers) is not a medical condition, but an identity.
In children, although it's an identity, it's also considered to be a medical condition, and it's claimed by many transactivists that it's important that children have medical treatment as soon as puberty starts.
Adults can opt for either the totally medicalised path or the totally unmedicalised path, or a mix if the two, taking whatever they want to suit their own personal tastes and desires. Whether they should be viewed as victims suffering from a distressing psychological condition, or people with an identity which is comparable to being gay, is also dependent their own whims.
Some of these people have what you're thinking of as gender dysphoria. They desire medication and surgery to make their bodies look as much as possible like the opposite sex. These are the people you seem to be thinking of, but there are now many different reasons for adopting a trans identity which you seem unaware of.
Some males who identify as trans are just crossdressers taking their fetish to an extreme. Some of these also desire medical transformation to make their bodies look female. This is autogynephilia.
Some of these men recognise that their sexual fulfillment means that they need to keep their sexual organs. These are the men who claim to be women with penises. They don't have gender dysphoria and they don't want medical treatment other than possibly fake breasts or cosmetic facial surgery. They are still under the trans umbrella.