At the risk of going too far down a rabbit-hole, we need to maximise the numbers of people engaged and trained in STEM skillsets, while also enabling the people who want to go into our hugely valuable creative sectors, and providing useful life education to everybody, including people who don't have the inclination or ability to do either. In order to do that you need to identify who to give the relevant education to, and ideally to do that at a reasonably young age.
I think the years 7-11 maths curriculum is probably pretty well-targeted at useful life skills - it's reasonably stats and geometry heavy and focuses on transferable skills. Teaching this well (which is a challenge caused by the paucity of good teachers willing to work for peanuts) is sufficient for all the above purposes. Teaching it again between 16 and 18 to people who didn't pick it up the first time, or have changed their priorities, is reasonable.
Teaching more maths post 16 to people who have made their life choices and don't want it doesn't serve any purpose whatsoever. Suggesting it is out-of-touch and absurd, which is perhaps not surprising coming from Sunak.