This person writing about BSD for linux users makes the claim that one challenge linux distributions face is that there's no well-defined "core" to a linux system
bsd has kernel and one libc variant, and that is probably the point they try to make - that bsd has one standard libc, while linux has a selection (eglibc, glibc, uclibc, dietlibc, newlib, etc). also *bsd distros are less varied than linux ones.
tinycore is not a standard linux core. it does not come with compiler, it does not support a lot of filesystems and devices. you need to add those essential tools to it first.
linux from scratch book pretty much outlines what's the essential base for a linux system, that after setting up can be extended into a working installation without the need of external tools.