The politics and sexuality were always in these stories. They were just more familiar, so they don't seem as self righteous. The Moon is a Harsh Mistress is a classic example of a story with sexuality and politics in old timey sci fi.
Most of what I remember is the author using the action of the story to carry the point across.
The same is true of Star Trek ToS, and most of what I remember from deep space nine.
It is not that I am opposed to the ideas of flexing sexuality and politics in science fiction- quite the opposite. Take for instance, the culture series by Iain Banks. Fantastic work where If there is some lecturing done, it seems to fit smoothly into the flow of the work.
I mean, I think it's maybe just that a certain subset of the readership are now unhappy with any discussion of sexuality (I suspect that people like this simply didn't really read sci-fi in the past). In particular, look at Heinlein; a lot of his stuff would be very out there _today_ (the Moon is a Harsh Mistress is quite mild by Heinlein-weird-sex-stuff standards).
The complaint about politics is too silly to take seriously at all; sci-fi has _always_ been about politics, to the point where it is difficult to come up with non-YA examples of politics-free sci-fi.
Scifi has always been an exploration of the human condition within certain circumstances created by fantastic technologies. The human condition is made of politics, sexuality, philosophy, ethics, identity...
I am perfectly happy for science fiction to offer commentary on social issues. That's one of the strengths of the genre! But to do that, you need to be subtle and lots of modern authors don't even try to be subtle any more. And as a result, their attempts at social commentary are absolutely insufferable to sit through.
Nothing subtle about Star Trek's political stuff.