Re: Multi-tasking..as a matter of interest..
It could be a result of those voting actually having read the documentation? Here's a quote directly from the Process Manager documentation that you linked to, to substantiate your claim that "MacOS had full preemptive multi tasking from System 7 onwards":
This chapter describes the Process Manager, the part of the Macintosh Operating System that provides a cooperative multitasking environment.
As mentioned by several others, the classic OS wouldn't go anywhere near pre-emptive multitasking until 8.6 in 1999 via the Multiprocessing Services. To quote the engineer that actually wrote the thing:
I rewrote the nanokernel in OS 8.6, adding multitasking, multiple address space support, fully protected memory, multiprocessing support, a high performance scheduler, enhanced power management. ... The upper layers didn't exploit much of that support in 8.6,
So people are probably reacting negatively to your post because it's counter-factual.