I suspect you have misunderstood Archbishop Ganswein's remarks.
Certainly that is the impression I get from a Google translation into English of his Karlsruhe speech that was given in German. He was certainly not downplaying the importance of homosexual behaviour, but pointing out the difficulties that come up when secularised society refuses to recognise Catholic teaching in moral matters (such as divorce, marriage, etc.).
It might be good to point out that as well as working for Pope Francis he remains - as far as I know - secretary to Pope Emeritus Benedict XVI.