No, it doesn't need a source. It's not mysterious. To meet the demand, age verification would be necessary. What's your claim?
I guess you could be saying that the regulators were carrying out legal duties like blind automatons, without giving a thought to the way their requirements would have to be met.
My claim is the documentation about the ICO investigation and the resulting fine.
It's an entirely different piece of regulation to the "horror" of the OSA.
It's not hard - you're not allowed to target adverts for children - if Imgur aren't able to agree to that, they are within their rights to decide they don't want to properly safeguard the private information of children and withdraw from the market. That many other providers haven't thrown their toys out of the pram and complied with the law would show they decided if they can't tailor ads to children they wouldn't be able to turn a profit in the UK.
The governments of the countries that dabbling into the "think of the children" laws should build their own "safe" internets for their citizens, walling them in, requiring them to "verify their age" before letting them out of their cages into the Internet.