Currently in several states, members of the LGB/T community are at risk of not being able to hold jobs, much less obtain reasonable and affordable healthcare. Those who are transgender or transsexual are completely denied coverage of related treatments and medication based on their state (sometimes extending as far as physical examinations and blood work to check hormone levels).
According to the APA's DSM-V, trans people have a "gender dysphoria." Dysphoria is a type of depression that can very potentially lead to suicide. Denying treatment to these people is not only irresponsible, but also inhumane.
So why include rights for lesbians/gays/bisexuals, if this primarily focuses on those who are trans? Because both before and after transition, their sexuality can be a very ambiguous thing