In the Mabinogion, Bendigeidfran (Bran the Blessed) is mortally wounded and asks his seven surviving men to cut off his head and take it to London and bury it on the site where it is said that the Tower of London now stands. While the head remained buried, no misfortune came to the island of Britain, but Arthur thought he could defend Britain by his own might and so he dug it up. But he was overconfident and, as we know, he lost at Camlan and that ushered in the Dark Ages.
Corbyn wants socialism in one country and thinks that being in the EU will stop him doing that, hence Lexit. Leaving aside the fact that the voters of the UK are unlikely to vote for a very left-wing government in sufficient numbers to win outright, this plan assumes that Labour will keep on winning forever and thus we will keep our little socialist utopia. Nice though that might be in theory, over the past decades, the Tories have been in power more than Labour. The moment a Tory government got in, they could undo all Labour's legislation and there will be no EU minimum standards to fall back on. Lexit would not be permanent. We'd soon have the hardest of hard Brexits. Why can the Corbyn supporters not see this?
Article in the iNews saying that if Labour want to win an election, they should argue for a left-wing Brexit. I really don't agree because they will shed Remain voters who will turn to the LibDems.