"E.g., even if Windows has only 90 percent market share, it somehow makes sense that Windows would attract upwards of 99 percent of all security exploits. And that conversely, the Macs 4 percent market share should not translate into a 4 percent share of exploits. The conclusion here being that just because Windows has a disproportionate share of security exploits, does not mean that it has disproportionately more vulnerabilities."
HACKERS DON'T USE MACS.
Windows is easy to get and runs on cheap hardware - the same hardware on which hackers run FreeBSD or Linux or whatever.
Hackers do use FreeBSD and most of the other shell software included with Macs.