Re: How about accepting personal responsibility?
Just because it worked for you and your kids turned out fine doesn't mean it is the right solution for everyone else, and it is also a very ignorant and inconsiderate premise to work on and has numerous serious consequences.
The majority of parents are not computer literate enough to have any clue about this or how to deal with it, they know how to turn on their computer, use facebook and send email and not much more.
Some parents work long hours and simply do not have the luxury of being able to supervise their kids computer/internet usage.
I have 4 kids, and it simply is not possible for me to supervise them all at the same time, and if I did it one at a time, then I would only be able to allow then access at the weekend and would get nothing else done. So yes I absolutely have to rely on other software solutions to control what content and websites they have access to. Luckily I am very smart and very computer savvy, but even I am not infallible.
Safe use of the internet also requires a certain amount of savvy knowledge and experience, most parents do not have this, and neither do young kids, who will just click on and download anything, the result of which is spyware, malware, browser hijacking etc installed on yours or their computers, identities stolen, passwords hacked etc, which is very serious of your kids are using your computer, or their computer can access others on the home network. So every device should absolute have a good anti-malware product installed at bare minimum, to not do so is pure stupidity.
Then there is the fact that simply "trusting" your kids not to do or look at anything they shouldn't on the internet, could land you in a lot of trouble, and you could find yourself with the police and social services knocking on your door. And if your kids have gone to school and told their friends "My dad lets me do whatever I wan't on the Internet", then pleading ignorance probably isn't going to help you.
Once your kids get to secondary school and start going out alone and staying with friends, then it is game over anyway, as they will be using computers at friends houses that you do not control or have access to, but you should certainly be making the effort to take responsibility for what comes into your own home, not only for your kids, but for your own sake as well.
So I would have to urge anyone NOT to follow your advice, and to definitely use 3rd party software, but simply to take the time to perform routine checks to make sure the software is working as expected and doing what it is supposed to do.
There are plenty of online resources to help you be safe online and keep your kids safe online.
such as: https://www.nspcc.org.uk/preventing-abuse/keeping-children-safe/online-safety/
I would also recommend all parents setup OPENDNS at home (www.opendns.org), this is pretty infailable as it is not software and is a setiing at router level, so affects all devices connected to your home network.