The reason they are for LGB only, explicitly dropping the T, is because modern transgender activism redefines homosexuality to be attraction between people of the same gender identity, rather than the same sex.
As a result, you have situations like, for example, males identifying as lesbians expecting actual female lesbians to be open to dating them, and accusing them of transphobia if they decline. This is a problem as by the usual/previous definitions, the former are heterosexual males who are imposing themselves on homosexual females.
This sort of thing is what the LGB Alliance was set up to oppose, given that most other gay rights organisations (Stonewall in particular) have fully immersed themselves in the ideology of gender identity.
As a result, you have situations like, for example, males identifying as lesbians expecting actual female lesbians to be open to dating them, and accusing them of transphobia if they decline. This is a problem as by the usual/previous definitions, the former are heterosexual males who are imposing themselves on homosexual females.
This sort of thing is what the LGB Alliance was set up to oppose, given that most other gay rights organisations (Stonewall in particular) have fully immersed themselves in the ideology of gender identity.