I think you’re proving my point a little. You’re treating the costs as obvious and enormous, while treating any potential benefits as essentially zero.

We have to accept that there are policies with obvious and enormous downsides and essentially zero upsides, because they exist and get tried from time to time. Eastof (and the article) are providing an argument that this is one of those time. A pretty reasonable one too, I forget the implementation details of the UK scheme but in Australia and most of Europe the authoritarian bent of the people implementing these age restriction bans is concerning - it looks like they're setting up a general purposes minority targeting systems. I'm not sure how they're going to justify that and I don't recall seeing anyone make a reasonable argument to justify it yet beyond "We can and we're going to. Trust us and think of the children".

Your argument seems to be that the issue is more nuanced than anyone else is saying, which is cool and all but then it sits with you to identify what the nuances you want to talk about are. Pointing out that someone else has identified different tradeoffs than you have is something of a given since that is the case with almost any pairing of people.