The tl;dr from the article (which is actually worth a read):
The very short version: Unix PIDs do start at 0! PID 0 just isn’t shown to userspace through traditional APIs. PID 0 starts the kernel, then retires to a quiet life of helping a bit with process scheduling and power management. Also the entire web is mostly wrong about PID 0, because of one sentence on Wikipedia from 16 years ago.
It’s unused, you can go ahead and kill it.
Kernel: dies
The last time my community found a PID.0 in our midst, he was beaten downtown in broad daylight by over a dozen assailants, no witnesses.
Mr. Anderson, Thank you for your analysis/work and well written treatise, on PID 0. I enjoyed learning more about Linux & Unix and a bit of history thereof as well.
I read that in Agent Smith’s voice.