Why is the lgb and the T grouped together

Not what I was saying, sorry for not making it clearer. You have to take it in context of MrSmooth's response to my first post. He stated something along the lines of "You get that being gay and trans* are different, so how could we help fight for each others rights?" I used the example of the 1960s Civil Rights Movement to clarify how people can be different but still support each other.