There are a bunch of studies over the last decade or so finding that teens (i.e. teens to ~28 year olds today) have shifted the balance of their social interact

There are a bunch of studies over the last decade or so finding that teens (i.e. teens to ~28 year olds today) have shifted the balance of their social interactions away from in-person contact to online communication. If the same thing goes for sexual topics, that would quite neatly explain this pair of interactions. Debating sex on social media or posting adult content online is publicly visible, hence "people are sexualizing everything these days!", but it's plausibly also an replacement outlet for what isn't happening in person. (The other, simpler, take is that online accessibility just means we see an increasing amount of everything, even if the number of people involved is declining.)