The greens are filled with communists for example.
Or the literal communist party, Die Linke. Why are they never referred to as the extreme left.
It's definitely not true that people never refer to Die Linke as extreme left. In fact, all kinds of people - including prominent politicians from e.g. the CDU - refer to Die Linke as extreme left.
This is not commenting on whether that is a correct moniker or not, I'm just pointing out that your dichotomy is nonsensical because the thing that you suggest to not be happening absolutely is happening.
Feel free to read the chapter „Linksextremismus“. It talks about various violent Antifa groups and other cases. Keep in mind that the definition of „extreme left“ refers to organizations that want to replace the basic democratic system with communism or anarchy (according to the German constitutional court).
It does not necessarily include „political craziness“ that we may disagree with. The point of these legal descriptions of organizations is not to be used as a political weapon for parties you don’t like. You have to do some significantly malicious stuff to be considered as such.
The AfD, like all political parties, is simply a coalition of various smaller subgroups.
It’s by no means “extreme” right in entirety. Yet, leftist parties harboring actual communists are not labeled “extreme.”
While the party started with a different background, by now voters and members do know about these majority positions and thus support them.
As the time of writing, six different extreme left groups are tolerated within Die Linke and are also financed by their members. All of these groups are currently being watched by the government secret service.
The greens are not filled with communists. They would feel very unwelcome there, given the capitalist move the party did in the 90s.
Die Linke is also not a communist party. It supports capitalism, but targets a social capitalism, like the CDU did in the 50s and the SPD did until the 80s. There are communist parties in Germany, like the MLPD, but they do not get many votes. Background here is that in a divided Germany the communists were not popular in West germany, also most of them got killed by the Nazis before, and on top of that West Germany banned the main communist party already 1956.
Also, rightwing politicians do call "Die Linke" (incorrectly) extreme left, and accordingly the CDU/CSU has a mandate to never cooperate with them.
This is untrue and you will only have to go so far to read their party program to find out it isn't.
It took me all of 5 seconds to achieve this enlightenment. You should try it sometimes.
But indeed, the program now does distance itself from social capitalism specifically and gives further reasoning to why. I wasn't aware they spell it out so clearly now. We can still argue about how much capitalism would be left when following their program - like when the means of production are owned differently, but used similarly - but I have to give you a point there. My comment as written was not correct.
German law tries to protect against anti-democratic groups and categorizes them as extremists (including left wing extremists) if they a threatening democracy.
In practice that means that group is then surveilled. If there is evidence that the group tries to overthrow democracy, they are banned.
Die Linke is in many ways _more_ democratic than other groups and parties as they support direct democracy and workplace democracy.
Die Linke tolerates antidemocratic hate groups within their party and is a financial sponsor of others. All of this is common knowledge, all of this can be looked up easily.
> Die Linke is in many ways _more_ democratic than other groups and parties as they support direct democracy and workplace democracy.
I know quite a lot of parties that were never once watched by a government watchdog, nor do they continue to support extremist groups, nor do those other parties continue to attract extremists at their demonstrations, nor do those other democratic parties have a continued problem of antisemitism within their ranks, nor do they have a dark past and continue to employ people at high ranks that were leaders in that past.