South Korea has had testing and tracking in place for years. Every other country is way behind. Testing will be part of helping gather data that will allow decisions to be made to relax the rules but it will take time to ramp up testing.
Nobody is 'advocating' herd immunity it is just a fact that without a vaccine we will end up in a position where herd immunity is a reality. You are behaving as if the British government proposed doing nothing except letting herd immunity deal with it.
Vaccines are over a year away and treatment options at the moment are not promising. The UK policy of social distancing to flatten the curve, massive boosting of NHS resources, supporting business and workers and shielding the vulnerable is as good as it gets. Give a bit of credit where it is due.