This was originally posted on his Facebook. I'm posting the plain text because I think Facebook requires an account to see it, but you can see the post by searching for his Facebook account "Nathan J. Robinson" and finding his most recent post there.
No, oligarchy is not a key tenet of socialism. You may be thinking of Stalinism.
Pure socialism would tend toward extreme democracy, where the government controls all things, but all workers have equal say in what the government does.
The editor[1] of Current Affairs describes himself as a libertarian socialist[2] -- someone who strongly opposes centralized rule by a small number of people (or single person).
For the two months it ran, there was an organized government [0] (conseil de la Commune) which made decrees, there was an army of ~200,000 soldier [1] and there was a Jacobine police which assassinated many people (including other "Communards") without trials [2].
This radicalization in a very short time (two months) was denounced by many other "Communards" and people like Victor Hugo [3]
[0] https://en.wikipedia.org/wiki/Commune_Council_(Paris)
[1] https://en.wikipedia.org/wiki/Paris_Commune#National_Guard_t...
[2] https://en.wikipedia.org/wiki/Raoul_Rigault
[3] https://en.wikipedia.org/wiki/Victor_Hugo#Political_life_and...
Citation:
Victor Hugo was harshly critical of the atrocities committed on both sides. On 9 April, he wrote in his diary, "In short, this Commune is as idiotic as the National Assembly is ferocious. From both sides, folly."
Yet he made a point of offering his support to members of the Commune subjected to brutal repression.
See also: https://en.wikipedia.org/wiki/L%27Ann%C3%A9e_terrible
But even if they agree, the proletariat is not a few people.