Obviously you also have people who actually support the far right ideologies but lot of these voters were recently found to be willing to switch to a new far left party as soon as it runs at an election (catapulting it to 20 % off the cut at a federal level); same motivation. Protest votes
https://www.berliner-zeitung.de/news/sahra-wagenknecht-parte...
The voter movement from center left to far right is from the official election results from a few weeks ago.
Most democracies are pluralistic with more parties which is why the Germany anecdote makes more sense than the US one
Considering the horseshoe effect, this is totally plausible.
> The horseshoe theory does not enjoy wide support within academic circles; peer-reviewed research by political scientists on the subject is scarce, and existing studies and comprehensive reviews have often contradicted its central premises, or found only limited support for the theory under certain conditions
The people who desperately dispute the horseshoe theory are usually politically extreme themselves and hate the thought of having such similarities with the opposite end.
I’ll just say this: horseshoe theory is wrong because when there are similarities they’re inconsistent and shallow. If that wasn’t true, political scientists would be able to write papers about the consistent and deep similarities, but they can’t so they don’t.