It's simply not true that UKRI don't allow you to charge APCs to grants. I've costed it in to my current grant with no problems. They also provide funds to institutions to support open access publication, that academics without grant funding can access.
Generally people without funding support e.g. from 'developing countries' are able to publish for free via a fee waiver, as the article suggests. This new policy also means they're actually able to afford to read the research in the publication they're submitting to.
If you're arguing that the academic commercial publication model makes no sense and is in desperate need of wide-ranging reform, I agree with that. But I think this is a step in the right direction because at least it makes research accessible.