I cant say I can be bothered to read the article, but maybe the OP's headline is misleading.
I am not aware of any "extreme left" groups having been in power in any european country.
And if this is meant to be about trans ideology, this have come from middle of the road, middle class, individualists who think the world, whether the working class in their own country or those whose countries have natural wealth, should work to provide them with the benefits.
Lets face it even Corbyn wasn't that left wing, it was more a personality cult, which (as UK politics is treated as a reality show by the UK media) set him up as a target for the MSM.
The rise of the far right in Europe is not to be celebrated because it is as a result of just how useless most left, even liberal, political parties are. Or possibly how easy it is for the rich owners of newspapers and tv news stations, to present the more communal, fair shares for all, society is not possible. The endorse the dog it dog world that means that the US one of the richest countries in the world has the worst health service.