Simple. You're drawing too much power. In at least the newer versions of the Pi, 2.0 revision and some 1.0, the USB polyfuses have been removed. This is expected behaviour, and you really can't do anything about it.
Basic answer:
Hotplugging a USB device will cause a spike in current demand, thus causing the reboot. If you want to hotplug, you will have to use an external powered hub (powered being key, otherwise it just draws from the Pi, causing even more issues,) or plug the device in prior to boot.
More info:
You can technically change this, but it requires hardware modification like bypassing the F3 polyfuse, replacing capacitors, replacing 0R resistors at the USB hub, etc. However, these aren't suggested as they would obviously void your warranty and can easily fry your Pi if done incorrectly, not to mention changing the core way the Pi works.
Links (You mentioned you had read the discussion about this, have you seen all of these?):
Old official forum post started back in 2012
Basically a duplicate - has 3 more posts than the one above
Specifically states the issue as a WiFi dongle
Raspberry Pi reboots on plugging in a USB device - From this site.