I've been a Ubuntu user for a few years now, and it generally ranges from cumbersome to downright difficult to upgrade to the newest Firefox version. There's a reason hacks like Ubuntuzilla exist.
In any case, if you're the kind of person that knows what actual features you will gain from FF7 over FF4 (other than just "sweet, a higher numbah"), you're a power user and should know better than to make the complaint he did - you should be able to do the extremely mild googling required on your new, unfamiliar OS to make it happen.
On another tangent, this kind of comment in the article is one of the big problems with FF deciding to do away with minor numbers and make every release a major number. "But FF 4.0 is so old, we're up to 7.0 now!! Bad!!" when it was the current release a mere 103 days ago.