You can, and should, argue about the effects but the core of the OSA and how it can be sold is this, at several different levels:
One, most detailed.
Sites that provide user to user services have some level of duty of care to their users, like physical sites and events.
They should do risk assessments to see if their users are at risk of getting harmed, like physical sites and events.
They should implement mitigations based on those risk assessments. Not to completely remove all possibility of harm, but to lower it.
For example, sites where kids can talk to each other in private chats should have ways of kids reporting adults and moderators to review those reports. Sites where you can share pictures should check for people sharing child porn (if you have a way of a userbase sharing encrypted images with each other anonymously, you're going to get child porn on there). Sites aimed at adults with public conversations like some hobby site with no history of issues and someone checking for spam/etc doesn't need to do much.
You should re-check things once a year.
That's the selling point - and as much as we can argue about second order effects (like having a list of IDs and what you've watched, overhead etc), those statements don't on the face of it seem objectionable.
Two, shorter.
Sites should be responsible about what they do just like shops and other spaces, with risk assessments and more focus when there are kids involved.
Three, shortest.
Facebook should make sure people aren't grooming your kids.
Now, the problem with talking about " a total surveillance police state, where all speech is monitored," is where does that fit into the explanations above? How do you explain that to even me, a highly technical, terminally online nerd who has read at least a decent chunk of the actual OFCOM guidelines?
Sad times...
You can always exaggerate and cherry pick bad instances from anything. What you are doing is similar to this. There were a few Samsung phones that blew up and caused injury. You now characterise all phones as being harmful and dangerous to society.
Edit: I do agree you should have a google-findable website which lists the objective characteristics of your product. If you call that advertising (I call it a "release", and I reserve the word "ad" for anything that has emotional appeal and caters to the indifferent/uninformed), then I agree.
I agree with you. Sometimes simply being the first mover businesses/solutions/software get name recognition and an unfair(?) advantage that greatly diminishes overall value by blocking better products from emerging.
To put if fairly, some things are so bad it'd be an improvement NOT to have them, so someone else could do a better job and everyone would be better off. Examples.. Emscripten, Python, Bluetooth, Chromecast, any IoT device so far created..
It’d be like saying an 18+ limit for buying booze means full DNA tracking because otherwise we don’t know if people are over 18 or just look it.
I completely disagree that even a tangentially related, much weaker concept ("having a list of IDs and what you've watched") is "second order" effect. This is a question relative to one's values, which is at the heart of the discussion, but as I'm concerned that cartoon version is a zeroth order effect - much more relevant than all the other points you make, which are at best less important (some might be completely irrelevant to me).
I couldn't care less about the technicalities cooked up by ofcom. Those will be left for a judge to decide and will depend on the political winds. Again, I'm just answering your point - "requiring X if kids are involved" is on the face of it obviously absurd and bad. And the analogy with alcohol, even though not great, might help make it clearer: to the extent that it is enforced, it is absolutely the case that it introduces a much weaker form of mass government surveillance.
The distinction clarifies the idea: if every store was required to check your ID digitally, in real time, and storing that information (which, mind you, makes it trivially accessible by anyone, in particular law enforcement), then the government has arbitrary power to stop anyone from buying anything ("oh, I see your ID is associated with X - sorry, we can't serve you right now" - replace X with your favorite group, idea, arbitrary law), to track their every movement (since you need to buy things fairly often), etc.
The scale and functioning of the internet is what distinguishes it from the physical space.
Just because you have a good master, doesn't mean you're free. You're only free when you're not not subject to anyone's good will towards you. I'm not an anarchist - there are real problems and there are laws that are necessary to solve these problems, your examples are clearly neither and so are on the face of it, absurd and laughable.