Can we at least consider that there might be a psychological impact of the fact that in one afternoon you can see more horrors and more nudity than 99.999999% of the world would have seen in a lifetime two decades ago? That there is so incredibly much disturbing content and porn on the internet that the expected reaction is "meh", followed by moving on to yet more violence and porn? That there is so much porn that the craziest fetish you can imagine probably doesn't just exist online, but has an entire website dedicated to it?
It is not just a difference of quantity either. The internet trains you to just move on from things which would have been life-changing events had you witnessed them in the real world pre-1990. Do you really think seeing a picture of a mass grave on the internet is the same as seeing one in real life? Do you think even seeing one in real life now is the same as seeing one in real life before it was possible to just ask the internet for thousands of pictures of one?
In any fair comparison, the internet is absolutely nothing like real life.
In this decade, in the US? No, you are right. Otherwise? It's easy to find examples.
A sample of comments from this thread that I'm trying to argue against:
> That stuff was there during the BBS days as well.... You wrap your kids in cotton and stifle them throughout their childhoods with your helicopter parenting...
> Sure the internet is a HUGE medium, and it's a lot easier to get access to that material using the internet, but that content's been around for almost as long as we've had photography.
> When will people understand that people online is no different from people you meet in real life. Some are shady, some will cause trouble if you talk to them, and violence exist everywhere?... 24/7 supervising is not healthy.
> Is it okay for you to force your child to wear a wire to school? Is it healthy to use the tapes to intervene in her conflicts?
Whereas I say that the internet is not just the same old stuff we've always had, it does affect us, and not wanting your 10-year old to watch porn or beheadings is not the same as wanting to watch them 24/7 and force them to wear a wire to school.
In general, the reinforcement learning present in humans mean that neural systems that are activated more are more influential, easier to activate, etc.. Exposure to violent media unsurprisingly results in increased availability (basically, increased access speed) of violent cognitions and behaviors, and lowered emotional responses (which is not a good thing -- it is very good to be disgusted at violent images, this is indicative of a trait called empathy which can be very adaptive in even the modern world).
Humans are not designed, evolutionarily, to disbelieve things we see. In our evolutionary environment, everything we saw was real. Special effects did not exist. It is actually cognitively effortful to disbelieve -- making research participants complete distractor tasks while having them discriminate between information marked, explicitly, as true or false causes them to be less accurate at judging. When you see a video game character kill someone and experience reward, that is an observational learning experience that is associating positive valence with violent behaviors.
Within the scientific community there's virtually no disagreement on this topic. Denying it is in the same class as denying climate change.
There is definitely a causal link between violent media consumption and violent behavior. Violent media consumption is neither necessary nor sufficient for violent behavior, but it is causal.
(This also does not imply that violent media causes large violent outbursts -- heightened availability of aggressive behavior could manifest as simply as being more easily frustrated or having a slightly quicker temper. But very small effects build up over time, sometimes into large amounts of lost value.)
I suppose your rhetorical question could be read as a value statement, in that it's ethically subjective whether violent behaviors caused by violent media are "bad". But since you seem to care about drops in real-world violence, I'll assume that isn't the case.
People ask me all the time how I know what's safe online versus what's not, and the only thing I can say is experience. I've fallen for enough scams and clicked enough malicious links to know what they're going to look like.
Those are all there in the real world, too. You can't protect kids from anything harmful or scary, nor should you. Stumbling across a porn or horror site is probably more traumatizing for the adult, anyway. It's like people have forgotten what it's like to be a kid! You've been told your whole life what to do, so there is nothing more amazing than the freedom to be treated like everyone else on the internet.