"The greatest shortcoming of the human race is our inability to understand the exponential function."
Do you not understand how limiting the exposure to infected individuals saves lives over the long term? This disease can kill. It is killing. Most people will not die, but some will. The more people who are exposed to an infected person, will in turn expose more. Eventually, the vulnerable - the elderly, the diabetic, the asthmatics, etc - are exposed and those are the ones who have a much greater risk of dying.
The fatality rate from confirmed cases is currently sitting at 4.05%. Roughly speaking, if one infected person comes into transmissable contact range with let's say 100 other people over the period they carry it, that's 4 people dead, while all of them who catch it can each then pass it on to another 100, at which point that's 10,000 people exposed.
Going into lockdown turns that 100 figure, into 10.
The government themselves have said the best case scenario is for the total number of deaths to be under 20,000. That's if everything goes to plan and these social distancing measures are carried out from right now -- You don't wait until a disease has killed that many people before taking action to stop the spread ffs!