2) I know a lot of parents worry about porn / the Internet. I was aware of porn and sex for pleasure rather than to pro-create, at about 11? Boys had it on their phones and were sending it to each other.
Interesting that you bracket knowledge of 'sex for pleasure' in with porn. I was always at pains to emphasise to my 9 and 10 year old DC that sex was fun and enjoyable with a partner you trust (disgrams and talk of babies can be quite off-putting without context, I think). That's fairly standard, isn't it? Nobody's teaching kids that you DTD just to have babies, are they?
But extreme porn, yes it's a worry for your generation and your parents, me included. (Vanilla porn being viewed by teens, I can't get worked up about, TBH, although much of it is tacky depressing shite).
Also, teens being filmed in compromising situations (BJs etc) and that footage being shared. Awful.
3) I don't know if you've seen the videos on Facebook but there are some gore/shock sites that contain images of weird fetishes, gay porn, infected vaginas and Mexican men getting beheaded with a chainsaw. We (us being my year group) saw these pictures and gross videos so much throughout year 10-12 and still today. We have become desensitised to violence, sexual violence and gore.
It's not necessary to watch to be aware, you know.
This was an epidemic in my middle child's OFSTED-beloved, top-rated, 'flagship' leafy comp in the London suburbs, along wit extreme porn, and it is true that some other parents seemed determined to remain in deep denial about it, along with the school leadership. A very knotty problem to tackle anyway.
( I removed my DC from that school and cancelled younger child's application and they both chose to resume Home Ed, BTW, which has cost us a bomb)
Your other points, however, isn't much different to the 70s/80s/90s, as you've been told. (Although maybe students are a bit more open about their shitty little ways now that fewer sanctions are available.)