It comes from the European party system.

Green parties who should be open for rational discussions when it comes to protect the environment of the state are basically the same as the left using the environment only as a tool to spread fear with no concept nor ambition to actually fix things.

Their policies include hate toward sovereign states and white people, full expropriation of the top performers of a country and massimigration. Especially the hate of sovereign states is a big problem since they aggressively try to spread their ideology to other countries not obey to their left extremistic values. They actively oppress smaller countries to follow their example, steal the top performers of other countries just to make them cheap working slaves in Europe or support riots from mobs following their agenda.

From outside you might think there is a healthy living democracy in Europe if you look at the different governments with the abundance of parties but in the end they all follow the same left contents.

"LEFTGREEN" is just to show these parties belong together.

The article is about a leftgreen terror cell continously doing attacks for the agenda without getting much recognition from the politics. In the mentioned case they burned parts of a railway track and injured a policeman.