Imgur's business model is ad sales and tracking users - that inherently requires collecting and protecting data, including vulnerable groups like children. Even if the UK rules are imperfect or possibly overbroad (I haven't read them), if a company choose to operate where a law applies, it's on the company to follow it or to challenge it through the courts, not to blame the regulator after the fact.
Because if we've learnt anything from the debate around the Online Safety Act, it's that the majority of people are so unbelievably addicted to porn they feel like it's a human rights violation to put up barriers to their access to it. While there are obvious privacy arguments against sharing your ID to access these sites the alternative is just not viewing porn. It's remarkable how unfathomable that idea is to entire generations of people.