There is a huge amount more than a kernel and a shell in a Linux distro. There is of course a package manager, which is usually written in python. There are all the utils to configure hardware and file systems (mkfs, mount, raid, ip, etc). The minimal Ubuntu is 63MB compressed[1], although it is not strictly comparable with a BSD base, as the BSDs include compilers in the base system.
Yeah... poorly phrased. I understand that there's more than a kernel and a shell; I started with Gentoo and worked quite a bit with RedHat/CentOS/Fedora before moving to Ubuntu and then to Debian.
The point was that what you get without selecting or installing anything else via a package manager is still apparently far less than what you get with a "base install" from a BSD (at least according to the article) and that that starting point is what I'm used to.
Gentoo is probably the most similar, as it has enough to bootstrap the system in the base (stage3), which is not surprising as it was modelled on BSD ports to a large extent. Although the BSDs will also include a debugger too. Linuxes generally got pretty hard to bootstrap reliably though, nad had binary packages earlier, which was where things diverged in base systems.
NetBSD takes bootstrapping most seriously - you can cross build it on any system with a vaguely functional C compiler, and it will bootstrap completely.
[1] http://blog.dustinkirkland.com/2014/08/re-introducing-jeos-j...