Back to the topic, here's an explanation http://www.maximise.dk/blog/2005/04/why-danish-programmers-a...
First of all, a number of nations in Northern Europe have done well in tech: Dutch (python), Norwegians (css, opera), Swedes (erlang, skype), Finns (linux, nokia) and Brits. What do these countries have in common? They are close to each other, they had strong universities within science or engineering before the computer revolution, they have been wealthy for the past 50 years or more and they speak English as a first language or as a strong second language.
You get nowhere in computer science without a good understanding of English. Virtually all the popular programming languages use English terms, most (all?) articles are in English and almost all documentation and tutorials are in English years before they are translated to local languages (if ever). So it's much easier for an average Scandinavian or Dutch teenager or college student to get into computer science than for an average Italian or Greek.
Oh, and they have all had a generous welfare states for the past 50-100 years so even back when computer science didn't pay well it wasn't so risky to go down that path.
Speaking as a Greek person who is also quite average, English was never a problem getting into programming. I live and work in the UK now, but when I first landed on these rain-sodden shores, my spoken English was bad and I had trouble communicating with people. Not so with computers- and I never had trouble with programming languages.
I think the same would go for Italians and even more so, since English has borrowed a lot from Latin, which is basically just an older form of Italian (with high school Latin, you can understand Italian perfectly well and even parse sentences on the fly as people speak to you :)
I think the reason why you may not find many Greeks or Italians, or generally people from non-English speaking countries in the history of computing is the opposite of what you suggest: any contributions they might be able to make are hard to transfer over to the English-speaking world. Any papers are in languages that are not understood in the English-speaking world and translation is not always available.
Since I'm not sure that this was written seriously, I'll point to anecdotal evidence of cfront, Stroustrup's C++ compiler, being the buggiest C++ compiler ever written. (Here's a bunch of bugs found by modern static analysis tools - http://www.i-programmer.info/programming/cc/9212-finding-bug... - but unfortunately I can't find the Usenet old posts telling that cfront was the buggiest C++ compiler of its time, and that early g++ was the next buggiest. The Unix-Haters Handbook has evidence from James Roskind who tried to make a yacc grammar for C++ - to a first approximation, an impossible thing to do due to a few goofy design decisions in the C++ grammar - and who said that every time when he tried to feed cfront input that would enlighten him with respect to some dark corner of the grammar, cfront crashed.)
I should say right away, I haven't found anything crucial and I think there are three reasons why PVS-Studio hasn't found serious bugs
The rest of the article doesn't seem to back up your claim really. It even says "The code is of high quality."
Regardless I agree the article isn't very good, serious or otherwise. If it is serious it uses one anecdotal piece to make a sweeping claim on the productivity of programmers across nations...
That said, Roskind's experience is more telling than the output of a static analyzer because generally and certainly with a compiler, actual testing shows orders of magnitude more issues than static analysis.