I have had BSD as my router for a few years in the past and used Linux for a few decades but I never got this “BSD is cleaner” argument. Linux has man pages and Google gives you plenty more practical resources when in doubt and nothing felt unstable compared to “BSD is more tightly integrated” statement.
Lack of community resource such as documents, blogs, StackOverflow answers and docker ecosystem just drove me away from BSD as I lose nothing by using Linux. The only thing I miss could be OpenBSD’s pf.
Maybe "cleaner" really means "more uniform", compared to the wide variety of Linux distros and their incompatibilities? Or like the word "intuitive", really just means "what I'm used to".
More uniform most likely. With FreeBSD can google some issue you’re encountering and the solutions you find are likely to be applicable, even with differing hardware, OS version, etc.
With Linux there’s been many times I’ll google some problem and the only solution that turns up is for distro Y which is mostly or entirely irrelevant to distro X that I’m running at the moment. This happens even with the big mainstream distros like Ubuntu and Fedora, but of course it’s worse with more niche ones.