In his comparison of Israel to IS, he wrote that Israel had engaged in “ethnic cleansing” of “Arabs or Muslims and Christians in Palestine”.
An image of Mr Ali-Diakides posing in front of a Hezbollah flag has also been circulated on Twitter.
Both wings of Hezbollah, which comprises an Islamist political party and a militia, are now banned as terrorist organisations since the Government were banned as terrorist organisations earlier this year.
The photo is believed to pre-date the Government’s banning of the group.
The JC understands a complaint with Labour's National Complaints Team has been lodged since his appointment as local party secretary, and that he has been suspended.
He is the son of a sitting Labour councillor in Haringey, Isidoros Diakides, who represents the neighbouring Tottenham Green ward and is reportedly a personal friend of Jeremy Corbyn.
James Austin, the former Stroud Green Labour member who uncovered the posts, said: “It is incredibly disappointing to find out that… they've chosen to elect someone who has openly expressed support for antisemitic, terrorist organisations.
“Clearly the Stroud Green Labour has no interest to opposing antisemitism and, indeed, it seems like it is actively promoting it. This is just yet more evidence that Labour both in Haringey and nationally is an institutionally racist political party.”
Adrian McMenamin, a Labour member who was present at the vote, told the JC that Mr Ali-Diakides’s views make him “in my view, not fit to be a member of the Labour Party, much less hold office”.
Mr McMenamin, a former Labour Party chief press officer, added: "The deeper question the Labour Party has to answer is why people with such vile views want to be members of a party that claims to oppose racism."
The Stroud Green Labour Party has previously apologised for planning a meeting in a pub to discuss such items as whether it is antisemitic “to say Naqba denial is a bigger problem than Holocaust denial”.
Richard Horton, the former chair of the ward party, resigned in March in protest of the party’s handling of antisemitism complaints, saying the “leadership, activists and apparatus of the party are so consumed by hate and outright crankery”.
A Labour Party spokesman said: “The Labour Party takes all complaints of antisemitism extremely seriously, which are are fully investigated in line with our rules and procedures and any appropriate disciplinary action is taken. We cannot comment on individual cases."
Mr Ali-Diakides has been approached for comment.
