Someone should kill that link, it is no longer a relevant argument. Linus was mostly talking out of his ass complaining about microkernels. His main gripes were specific to Minix and Mach which were popular academic projects at the time.

There are many ways to make microkernels nearly as fast as monokernels, while being much safer and modular with all advantages that entails. See QNX or Sel4 for modern implementations.

Meanwhile, Linux itself has been getting more and more microkernel-y with things like eBPF which because of the monolithic design make the whole kernel much more vulnerable than warranted.