I don’t think any gay people are unaware of that fact. If we are going to take that approach, we need to also ensure everybody else committing sins gets the same message, not just gay people.
The message I get from Fr. Martin and other priests is that gay people are not an extra-special group of extra-bad sinners. Especially in a society where huge numbers of people calling themselves Catholic are committing sexual sins right and left, as well as other sins.
I don’t think most people who bother to call themselves Catholic are truly in the dark, in this day and age, that fornication, adultery, divorce and remarriage without annulment, artificial birth control, abortion, as well as same-sex relations are considered sins by the Catholic Church. I realize there is a difference of opinion on how much these matters should be preached about in homilies at Mass and whether the homily is really for reflecting on the day’s scripture, and not on moral teachings. However, I see LGBTQ as simply another issue in this large pile of sins and issues, not some kind of special be-all end-all issue that we should be extra worried about.