I can compartmentalise, so I can see rule34 of a character in one context, then in the context of consuming the original media, it doesn't affect me at all/crop up in my mind.
onlyhumans
I was allowed to use the family computer growing up, but had limited internet access, I mostly used it for Minecraft: Bedrock edition. I saw others around me like my parents, teachers using the internet though, and playing YouTube videos in class or whatever.
In school I used computers occasionally, I played Minecraft: Java edition 1.15 on them which was what got me to get Minecraft at home, and I remember being taught Kodu, which didn't really use the internet either. I was taught how to use the Windows filesystem, and my classmates showed me the mrdoob website, which I found fun at the time, and now ironically use often for threejs.
In lockdown, I was given an Ubuntu machine by my parents for zoom lessons, which was my first real experience using the internet myself. The internet was not blocked at all on those machines, and I used it for Scratch as well with my parents permission - I had used Scratch on the school computers, so I knew what it was - which got me interested in programming, and also discovered porn for the first time on those machines, without my parents' knowledge. I didn't really understand the difference between how I was using Ubuntu with Firefox on those machines and Windows with Chrome or Edge or whatever it was at school, at the time.
When I was older, I bought my own Windows laptop with money I was gifted, which my parents installed Microsoft parental controls on so I could only go on for 3hrs a day, between certain times, and the internet, supposedly, except for certain whitelisted websites, was blocked. I discovered that my searching on the Windows taskbar search box, I could search bing unfiltered, and preview results and images, but with safe search on medium, and I couldn't click on anything. It would show results for FGM, but not for porn, which probably messed me up a little and shows that filtering the web is not the answer.
At some point, without me actually doing anything, although my parents suspected it was my fault, the internet filter disappeared, and I was able to play online games, download apps that didn't require admin access, and watch lots of YouTube (Mumbo Jumbo I remember I liked at the time), for about a month until I foolishly blabbed to my parents and they immediately reapplied the filter.
Later, I realised the Microsoft News app had an inbuilt web browser which you could only use to view one website at a time, with no back button or history, but again it was unfiltered. I was able to use it to watch YouTube videos, find porn, or indeed anything I wanted. At the time I took the existence of the internet and phones for granted, I didn't realise how recent inventions they were, but I gained that appreciation over time.
At some point, before my parents gave me a phone (which they applied parental controls to as well), my computer started acting slow, and my father said it might have a virus, and recommended and helped me with installing Linux on it. This was when I started seriously getting into and understanding my computer, I was still programming on Scratch, but I figured out how to use the package manager (snap, I was stupid at the time) to install Minecraft Launcher, and went through a series of playing on multiple different servers with my friends and family, the majority of which I paid for hosting of, or managed the free hosting of with Aternos.
Then they got me an iPhone, which they applied Qustodia to, which for the longest time I couldn't get around the web filter of - I had to go down to the laptop on my desk, or cumbersomely bring my laptop up to my bed every time I wanted to search for porn, but eventually I found this niche web browser which somehow managed to get past the web filter applied by Qustodia (which used the VPN feature), I also found this site appetize.io, which I did not use for its intended use of emulating iOS devices, but instead took advantage of the free trial which they gave you, and how the website was not blocked by the filter, but it let you use an unfiltered version of Safari within the emulated device. Which was obviously a worse user experience, as is a theme with these exploits, but it did the job.
That was when I really started getting into my computer, customising the OS and software more, really getting into coding, proper stuff like python and JavaScript, not just Scratch, and even made myself a very amateur looking website, but I was proud of it at the time, and now it's actually pretty decent, if I do say so myself.
Eventually I bought myself an Android phone, and started degoogling, and switching from Reddit (which I used on the iPhone) to Lemmy (this happened a while ago, this is not my first account), and really getting into FOSS, coding, and understanding how amazing and crazy the internet is, and phones and computers in general.
So my advice to any parent is to not try and control your childrens' internet access technologically, as they will find a way around it, even if it isn't the most use friendly. I felt comfortable sharing the methods I used, as they might not even work anymore, and there are doubtless many others and many new ones I don't know and that have emerged since. Talk to your children, explain to them why they should self restrain on parts of the internet, in a way you're sure they actually agree and aren't just shrugging you off, but also with the understanding that the best way to discover not to go to parts of the internet is to go there and be scarred, and they will likely learn like that too.
Obviously there is the exception of people on the internet trying to exploit them or meet them in real life, which you need to get them to tell you about if it happens, invading their privacy by reading all their messages is not the answer either; if I knew my parents were looking at all the LGBT+ and atheist stuff on the internet I was, it would have made it more difficult to see it, and I would be in a worse place now.
In a summary, children seeing information is not a problem, it is a good thing actually. As a parent, the best thing you can do is not to guard that information from them, but to teach them how to evaluate it in a critical manner, so they're better prepared for the real world, and don't grow up in a bubble.
Who cut his dick off?