That does not contradict anything the government said. All else being equal, of course smaller groups, in the sense of people seeing fewer other people, is better. That’s not the argument. Nobody is saying “we should see more people”.
All else is not equal. You pull the quarantine lever, you increase social distancing but you also increase local mixing. Costs and benefits. The right choice at any given time depends on the disease spread. Computer modelling and simulation tells us when there is a net benefit.