It's just sort of anachronistic. Caml was no more designed by people deep in Linux life than James Clerk Maxwell was into aviation or Christopher Columbus liked to visit the Massachusetts Bay Colony. They probably would have been, but the timelines didn't allow it.
Sure. The larger point was about Windows. You would or would not agree that people doing PL research on SunOS workstations (or whatever UNIX) would also not give a shit about Windows?
Windows didn't exist in 01985. I mean, Microsoft did release a product by that name at the end of the year, but it wasn't an operating system.
I remember that in 01998 or 01999 I asked Andrew Tanenbaum, a different European CS professor, what he thought about Linux. His impression was still that it was some kind of hobbyist project for people who (paraphrasing here and reading between the lines) couldn't afford a real computer. So I suspect that, even when Caml became OCaml, its developers saw Linux as belonging to the same crowd as Microsoft Windows, rather than to the systems they were used to.
But even that Windows/Unix OS dichotomy didn't exist when the programming language was designed. They might have been thinking about Unix vs. VMS, or Unix vs. GCOS, or Unix vs. Oberon, or BSD vs. System V, but definitely not Linux vs. Windows.