UK Universities in a Covid-19 World

I am just finding it hard to work out why the people responsible for controlling the Covid-19 pandemic apparently didn't recognise that requiring students to 'return' to universities was going to add to the problem,of controlling viral transmission. University students are usually in their late teens and early 20's. This is an age group that is not particularily vulnerable to a Covid-19 infection. So they may feel less pressure to take actions to suppress viral transmission. It is also an age group that is often experiencing new conditions and new connections for the first time. Traditionally, students tend to aggregate, live and work in areas where 'crowding is relatively common. They are encouraged to question things and to explore their environment. Although lots of the face-to-face teaching (along with field courses and practical elements) have disappeared from the curriculum, students are still operating (in many cases) under unfamiliar circumstances. It is also clear that the 'test and trace' facilities, that students can access, is generally far from a) convenient, b) accurate and c) good at rapidly finding contacts. I suspect that many students will be worried by suggestions that they may not be allowed to return home at Christmas but should remain in their hall accommodation. The worry is that students returning home could 'seed' outbreaks throughout the UK. But this was always very predictable (many of the current new lockdowns seem linked to outbreaks occuring in universities). Why did it not occur to the policy planners that a) encouraging people back to work, b) requiring the schools to commence face-to-face teaching and c) openning of bars and restaurants, combined with a restarting of university courses, would make social spacing less than easy. Social spacing (always harder as the weather gets more wintery) is actually the most important remedial action we can take to reduce viral transmission. It seems to me that too many things were 'released' from lockdown simultaneously. Perhaps prioritising and doing things in stages would have been a better strategy?