People do not say they are gay so that you will envision sexual behavior any more than people saying they are married is intended to create images of romantic trysts. GLBT people are growing more open and vocal in hopes that you will understand the bias we face and how that impacts our private lives.
The reason things are changing for GLBT people is that we are no longer nameless and faceless. We no longer accept religious judgement as acceptable justification for imposition on our private lives. It's much easier to subjugate and marginalize nameless, faceless people.
The world is blatantly heterosexually biased granting special privileges to protect heterosexual relationships. These privileges are based on sexuality and blanketed by marriage. Meanwhile, GLBT private lives are legislated in many states and countries to ensure that we don't enjoy those same privileges. It creates unnecessary hardship.
Inheritance, pensions, health care, taxes, social security, shared property, decision making during illness and in death are all impacted by this bias. If we remain nameless, faceless people, you will not hear these stories. You will hear only myths and stereotypes. Because you know us, it's growing more difficult to be convinced that we should be rounded up and placed in a concentration camp as one US religious zealot has proposed. It is more difficult for US legislators to consider jail sentences for homosexuals as has now passed in Uganda. It is more difficult in the US to make even the discussion of social equality illegal as just recently passed in Russia.
Once people begin to realize that we are not so different and that these bias' affect our private lives unjustly, attitudes change. If you ask me what I do in bed, I will tell you 'I sleep' and nothing else is your business. It should not be your business to deny me equality. Invoking the name of God to justify your bias is a sign of intrinsic spiritual disorder.