UCAS definitely want to move away from hobbies and activities, especially those associated with advantage, being a large part of PSs. That's the whole point of the change (or a major point). My own DS plays in a brass band - and in the end removed this from his PS because it took up characters and was not really at all relevant. Cambridge, for example, specifically discourage students from mentioning any extra curricular stuff. (to be completely clear, what they say is to do those things to be more rounded and because you enjoy them - not to get into Cambridge. It's v confusing to US applicants!)
When you look at actual UCAS info on this change, and not the BBC link, it is clear the third box is for anything extra specifically related to the subject(s) you wish to pursue. It's not about soft skills. It's about reading and engaging in the ideas in Economics Review/history books beyond your textbook /reading challenging literature widely/ entering essay competitions, maths olympiads.
They will never erase disadvantage as affluent , university educated parents , and private schools tend to have the time, wealth, staffing etc to support all of this but removing the idea that adding that you are captain of the rugby team , take regular ski holidays, go shark diving in Mustique, is probably a step in the right direction. I think parents who argue against this are probably arguing forma stance of thinking their advantaged kids will lose out. I am sure they won't/
On another note, it will also stop students wasting characters writing about their job in Tescos and make them focus more in their statement on their course.
I have got so bored over the years of reading PSs desperately trying to make working behind the bar in a pub relevant to , say, a geography degree, where they have written one sentence explaining what their EPQ has done to enhance their studies and a few words about the skills gained through their NEA, and a bit in brackets stating they 'also study maths...
I hope UCAS really invest in training teachers about what they want and do more to communicate clearly with parents. The whole system at the moment is a bit opaque, rather archaic and very convoluted.