The purpose is to stop the spread of a *novel* virus that no human being has ever seen, or has immunity to, but is deadlier than seasonal flu, for which there's no vaccine or therapeutic regimen, but no one knows with certainty how it's spread within human communities. I'm fine with shutting schools. And restaurants and bars. And even airports and cruise ships.
The biggest *carriers* were the millions of people traveling on planes, trains and cruise ships crossing between countries (and state lines), who ended up at music venues, amusement parks, pubs, bars, restaurants and tourist traps. That includes community transmission. The UK doesn't have special immunity.
