While technically correct, I don't get what you are implying here. Just let nature run its course? Cull the weak?

I'm not implying anything. I'm saying that we'll end up with herd immunity whether we successfully make and distribute a vaccine or not. There are two ways to get that outcome: the easy way and the hard way. The linked article is wrong because it suggests that the easy way is the only way.

You could argue immunity can always be obtained the 'hard' way, even for a virus that seems not to induce it, as when the last human succumbs the infection rate has effectively gone to 0.

We refer to those points as 'technicalities'.