Shonda Rhimes got asked this question from a clearly idiotic viewer and being Shonda Rhimes she took the opportunity to use the question to answer a much larger societal question.

Question: love your shows but why all the gay and lesbian story lines?

Answer: Because I believe everyone should get to see themselves reflected on TV. EVERYONE. And because I love all my gay and lesbian friends. AND because I think same-sex marriage is the civil rights fight of our era and back when being a person of color was the civil rights fight, people like Norman Lear put black people on TV and helped change some minds. So you know, it's gotta be paid forward. As long as we are willing to sit by while one person is not free, none of us are free.

And FINALLY: because as long as someone feels like it is okay to ask the question "why all the gay people on your shows", then there is still a HUGE problem that needs to be solved. It's like asking "Why all the black people on your shows". (Which is, in fact, why there are also a lot of people of color on my shows . Cause people keep asking. Like it's unusual. Which means we have a LONG way to go). Okay, done preaching.

Keep on preaching Shonda.  We are so with you.