It's less a "protected class of sin", and more a humane outreach to people who have long been marginalized.
Maybe not a "protected class" as much as "we don't talk about that anymore", what happened to the lectures about masturbation? Tying your hand to the bedpost? Besides being an open door for the church being mocked, maybe it's another area where understandings are a little more nuanced, today. (Does masturbation lead to rape? Maybe the opposite.)
The softening of views toward LGBT and gay marriage has more to do with evolved understanding that it's not simply a behavior... it's an attribute, of people who've really suffered, for something increasingly viewed as not being a personal decision.
Nothing prompts reflection like suicides of teenagers who've determined they're LGBT. Research suggesting this type of reflection is warranted: https://arstechnica.com/science/2017...teen-suicides/ Basically, in states where gay marriage was first legalized, the rate of teenage suicide dropped. Acceptance / hope are important things, especially to teenagers.