That's all of FreeBSD including userspace, not just the kernel. In Linux land you see more than that level of activity in just the kernel:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/lin...

I didn't say FreeBSD was abandonware, its kernel development has just been relatively stagnant for decades vs. Linux. Which shouldn't come as particularly surprising considering how much more adoption and investment there's been surrounding Linux over that time period.