IMO it's about avoidable deaths.
If we all wore masks indoors all the time, our death rate would be way lower. There are several studies that show that countries that adopted universal mask wearing early have death rates many hundreds of times lower than the uk (e.g. S Korea where deaths are still under 500 whilst we're at 45,000 or more despite the fact that they got the virus much earlier than us).
Wearing a mask is not difficult, plenty of children all around the world, including in many states in the US (so a culture where mask wearing not the norm) do it all day in school with absolutely no problems whatsoever.
How will the children in this country feel if they are bereaved due to covid and they know that there's a very good chance their parent would have survived if everyone else would have just worn a mask? If the government had mandated masks in schools? The science is pretty clear, sooner or later they'll know this.
How do you ever get over that and not hate the people around you glibly going on about 'it's just the flu' and 'I can't possibly wear a mask'.
Wearing a mask really isn't difficult, it's not painful or hard in any way.
However, a large number of people in the UK are too selfish to wear a thin piece of fabric over their nose or mouth to save someone else's parent or, indeed, the economy.
So, we're fucked basically.