Absolutely agree with you that he should address his argument.
That said, this is almost too obvious to point out, but it happens to be true that the Soviet Union and Communist China (and Vietnam, Cambodia, etcetera) murdered 100 million+[1] in the name of "building socialism", and it is quite possible that the original poster knows people from those countries who lost loved ones to socialism/communism.
Seen in this light, I'm not saying that OP's phrasing was the way to go, but it's understandable that there are people frustrated by this all too common style of ignorance. It's not idealistic to actually support socialism in 2011, it's simply ignorant.
At the risk of reductio ad Hitlerum, certainly an offhand comment in favor of "rational, libertarian Nazism" would have dominated response to the essay, yet we find it acceptable for educated people to make offhand[2] complimentary references to a polar opposite ideology that actually killed many more people.
Perhaps you are not familiar with the terminology... In most of the world, "libertarian" means libertarian socialism. The historically correct meaning. Some right-wingers in 1950's US appropriated the term to mean extreme capitalism. Discussed earlier:
The usual claims against communism don't apply, as libertarian socialists historically opposed both communism and capitalism. (In the senses you mean.)
I'm sorry, you're correct, I should have linked to the HN discussion, where steveklabnik does a good job explaining. I was very distracted and rushed when posting.
It's absolutely true that socialism is an overloaded term that can refer to anything from the European-style welfare state (hardly a hellhole) to far less pleasant dictatorships like Cuba to out-and-out mass murder like in Cambodia, China, and the USSR.
However, the post said "I believe my generation will overthrow the arbitrary and brutal authority of corporate capitalism and bigoted conservatism in favor of rationalistic, libertarian socialism driven by a scientific approach and a concern for universal social justice".
That sounds more like Pol Pot and Lenin than your standard EU bureaucrat. The latter usually pays at least lip service to capitalism and markets even if they often have a conflicted relationship with them.
Also, the thing is that we tend to take people at face value in most other areas. If someone calls for takeover by Hamas or Islamic Jihad or the KKK or the American Nazi Party or what have you, we usually do not go into detail to try to figure out exactly what splinter faction they belong to, or whether they represent "true Islamism" or "true Nazism", because we know that ideologies coming from that direction are a dead end and have killed millions of people.
Similarly, if someone calls for the overthrow of capitalism, it's incumbent upon them to explain that they don't really mean "overthrow" for real, but something more like Sweden [complete with multinational corporations like Ikea].
Postscript: For what it's worth, 90% of Indians and 93% of Chinese believe that trade and business ties are good for the country. These are still large, poor countries -- yet they are actually considerably more favorably inclined towards capitalism than wealthy countries like the US (now at only 66% favorable!)
Probably has something to do with the huge trade deficit of the US, if the US was a large net exporter that created many jobs, people's opinions should be different.
Certainly not as many as Communism or Nazism, but in the various manifestations of political Islam (aka Islamism), I think it's fair to say its adherents have killed millions.
In toting up that grim number I'd include the following, in which political Islam of one stripe or another was certainly a motivating force:
1. The Bangladesh Massacre, targeted disproportionately at Hindus. More than 3 million dead.
2. The Iran/Iraq War. Iraq started it but Saddam's avowed intention, to the extent it can be trusted, was to stop Khomeini from fomenting Islamic revolution in Iraq. Massive atrocities on both sides, 1.3 million dead.
3. The Algerian Civil War. 150-200 thousand dead.
4. The Janjaweed perpetrators of the Sudanese Genocide. At least 330 thousand dead.
The killers/combatants here were influenced by numerous factors, but even if you assign only fractional "credit", I think it is indeed accurate to ascribe millions of deaths to political Islam. Moreover (and this is I think the point you were driving at), I think it's fair to say that Al-Qaeda has genocidal intent even if not capabilities.
All of those damned governments were Stalinist. That means they believed in a dictatorship of the proliteriat and screw everyone else who doesn't believe in "communism".
Stalinism is just one branch of communism and it is such an obvious failure that generalizing it and making it the one and only true communism just shows your ignorance about what socialism is and isn't.
So one branch of communism, one that favours a dictatorship and favours state-owned property instead of public-property (which anarchism and other branches of communism favour), has killed millions.
It is idealistic to support socialism, it's ignorant to support Stalinism or Maoism or whatever dictatorship-favouring branch of communism you want to refer to. Generalizing that garbage is worse than ignorant.
He didn't make a cohesive argument to respond to. libertarian socialism? I don't argue with fools, but I will point him out to others in the hope that they'll save some time.
those brutal psychopaths happen to be the most effective form of peacefully organizing humans to provide stuff others want in voluntary trade ever created. There's a reason we see thousands of years of conquest, then the innovation that allows large safe investment in wealth generating ventures and a subsequent explosion in global standards of living and the decline of conquest. you might want to try reading a book as well.
But who am I kidding? the historical illiteracy of the post cold war era is all but absolute at this point. Rah Rah democracy.
Psychopaths aren't a problem until they start killing people. Yes they have a certain psychological profile but if you take away the serial killer part, nobody cares.