I don't know what the opposite of rose-tinted glasses are, but I think the article paints a misleading picture by leaving unstated how polished 10.5.8
wasn't. Sure 10.6.0 had some new bugs due to landing major new under-the-hood technologies, but there were no serious regressions. It was a rare major release where you could install it on day one and not end up regretting it.
Of course 10.6 got better over time, and 10.6.8 was the best release of them all, and it was followed by Apple's answer to Windows Vista. But that doesn't mean 10.6.0 sucked.