In the bottom link's list of eight bugs so far (one a day throughout July), only one occurs on the Mac, and that's with Safari. Six occur with — surprise, surprise — Windows IE, and one is in Firefox for Gentoo Linux.
The Linux Firefox bug belongs to 1.5.0.2, two versions back, and was fixed in 1.5.0.3, one version back. Reporting a bug long patched is an echo of the recent warning of a security hole in OS X after it was fixed, which was condemned by Macites as being FUD propaganda.
When listing outmoded browsers, why stop at Firefox 1.5.0.2 and IE 6? He might as well go back to Mosaic. Besides, it's more likely than not that Linux users are geeks and keep their machines up to date.
It will be interesting, though, to see how much larger the Mac ratio of browser bugs might grow over the month. I'd bet that if it does, Safari would be the culprit. But any report of a bug in a version of Safari or any other before the current one should be discounted.