Your original point seemed to be that FreeBSD is more secure than Linux. I'd say you haven't made your point.
He doesn't really need to.
I contend that if you are making an argument then it's up to you to support it. Clearly, he doesn't need to convince you. That's well and good but it still leaves the point as conjecture.
In the CS community, it's well known that BSD is more stable, secure, and the best OS for critical infrastructure, while Linux is more friendly, flexible, and better for hobbyists or businesses that can save money (by hiring cheaper Linux fanboi rather than expensive real computer scientists).
I always find it interesting that people want to refer to the outcome of applying a complex and nuanced term like "security" to some product as being "well known". Speaking as a member of the aforementioned "CS community" (a la Dijkstra :-) )
Referring to a commonly known fact, such as the security of BSD vs Linux, is not an argument.
Even if there happens to be a gainsaying fanboi present to dispute the widely recognized consensus reality.
I always find it interesting that people want to refer to the principal concepts of a conversation as "complex" and "nuanced" as a way appear more deeply thoughtful than the other participants.
BSD is not merely a security "product" it's the platform that the internet, and later the web, was built on and still runs on, to a large extent.
Please re-read my use of the phrase "well-known" in its proper context of me speaking about the real CS community. And by "real" I mean EECS engineers and computer scientists, not cloud-happy corporate consultants and l33t Geek Squad linux fanboi.