Ever Heard of the herd immunity? here is the link about
herd Immunity. There is no vaccine for covid19 right now so the goverment could be secretly trying to achieve this herd immunity by hoping that people that have been infected will create some sort of auto immune in their body
They cant really sacrifce the entire country's economy because of lockdown therefore most country has open up and let people work and do stuff as normally as ever ( Secretly hoping that herd immunity would be achieved naturally before a vaccine is created )
Herd immunity was proposed in the UK as the first response and the authorities later retracted their view, after probably witnessing the enormous load on healthcare system in Italy. This response from authorities will vary from country to country. For sparsely populated, developed countries with concentrated centers of population, the cluster approach will work and they will not have to play with citizen's lives in the hopes of herd immunity.
In poorer countries with huge population like India or Nigeria, people themselves seem to have accepted the fate that it will spread, no matter what. If you live, you live. If you or someone you know doesn't survive, well, mehhh. The govt will be happier with the herd immunity outcome. The problem is that coronaviruses are not like say, measles, smallpox or polio where immunity if for a lifetime. The most worrying phenomena is that it may only be seasonal immunity. That is why we can never give up on the approach of finding and isolating cases. This fucking virus needs to be starved of human bodies.