You can debug the kernel with kgdb https://linuxlink.timesys.com/docs/how_to_use_kgdb There is even KGDBoE to debug over the network.

I wasn't saying you can't debug the kernel.

I was saying that for practical purposes, debugging the kernel is needlessly hard.

As one example, say you are running the current ubuntu. A kernel panic will give you a bunch of hex addresses. How do you get a symbol'd backtrace of the kernel panic?

(if you can't get that easily, running kgdb won't let you do symbolic debugging either)