At the extreme ends, the left and the right are the same.

No Tardigrade they are not, stop repeating things that are not facts as if they are facts.

The idea of “Horseshoe Theory” has been floating around in the English language since at least the 1980s, if not earlier, with ebbs and flows in popularity. As the Wikipedia page (at least the English one) is relatively sparse on the historical origins and background of this idea, perhaps its worth a brief overview of the historical timeline.

Following his expulsion from the NSDAP in July 1930, Otto Strasser, the younger brother of Nazi party stalwart, Gregor, formed the Kampfgemeinschaft Revolutionärer Nationalsozialisten (KGRNS) Revolutionary National Socialist Combat Comradeship) as an anti-parliamentary “external opposition” fringe Nazi combat group. Later, in the hopes of merging with some other fringe sects, the Tat-Kreis (circle around the magazine Die Tat) and the Wehrwolf (right-wing nationalist Freikorps group), the KGRNS changed its name to the Schwarze Front (Black Front). In reality the Black Front never really amounted to more than a heterogenous collection of cranks and oddballs. The Wehrwolf group, already in numerical decline did not join the proposed merger and ultimately disappeared into the SA.

Otto Strasser’s political differences with Hitler were on the economic side — Strasser wanted a more explicitly anti-capitalist national socialism (although actual specifics beyond rhetoric were vague at best) — and in the international relations or geopolitical sphere, looked toward a rapprochement with the USSR to form an anti-Western “Eurasian” alliance (following the ideas of Moeller van den Bruck).

...

However Mohler was no neutral scholar, his thesis and book were as much a political project for the refounding of a radical neo-nazi project (Mohler remained an unrepentant Nazi until his death in 2003). Mohler became one of the founding theorists of the post war “New Right” and both influenced and was influenced by his French Kamarad, Alain de Benoist, theoretician of “la Nouvelle Droite”. Mohler’s rescuing of the Schwarze Front from the dustbin of historical trivia, also retrieved the Hufeisenschema, which became the basis of de Benoist’s “nether left nor right” concept of “metapolitics” of the radical periphery against the conservative centre.

https://eidgenossen.medium.com/the-nazi-origins-of-horseshoe-theory-5d9aa0ee277c

I think that the centre-right and centre-left parties that have traded power over the last half century have set the table for a situation in which it’s going to be one kind of radicalism or another. I’m not “both sides-ing” it. I’m not saying “Oh, we’re twinsies! We’re the same! Horseshoe theory!” No—I believe that only a robust left that is actually offering tangible improvements to people’s lives and taking on elite power in a real way has any chance of standing up to this right.

Since I’ve been on tour, I get questions like, “What should we do about the conspiracy theorists? Do we need more fact-checkers? Do we need more content moderators? Do we de-platform them?” I don’t think we can fact-check our way out of it. But when I heard Shawn Fain, the new president of the United Auto Workers, pounding the table about the greedy bosses not sharing their record profits with working people and leading this very innovative strike action, I thought, “You know, he’s probably doing more to counter this conspiracy culture then an army of fact-checkers, because he’s showing what actual left populism looks like.” When you have that in the public domain, this Poilievre nonsense looks like the counterfeit that it is.

Naomi Klein

https://breachmedia.ca/naomi-klein-steve-bannon-maga-doppelganger-populism-2/

If you only view politics as a game of elementary school cliques, you might say that the left and the right are meeting again. The left says Roosevelt got it wrong with the New Deal (because he left out so many people). The right says FDR was wrong for doing the New Deal in the first place. Therefore, the left and the right agree, right?

Obviously wrong. Obviously. Again, the important thing is why the left and the right think the New Deal deserves criticism. The important thing is what the left and the right want. The left wants universal liberation. The right wants us all in economic chains. They do not agree.

https://doctorow.medium.com/incomplete-vs-overshoot-ac7c838a3c0a

But the thing about political theories is they're developed and refined by lots of people over time, all of whom have their own ideologies and biases. These are often reflected in the models they make.

This is true of the horseshoe theory. UK psychologist Hans Eysenck was an early pioneer of the theory in the 1950s, but was also a staunch anticommunist. He deliberately developed the horseshoe idea to conflate communism and Nazism. He painted centrists as "tender-minded" (a term with no clear meaning, but meant to signify the moral goodness of the centre) compared with the "tough-minded" left and right.

In the 1970s, French philosopher Jean-Pierre Faye took up the mantle, claiming the left and right were equally totalitarian. This was aimed at condemning rival French philosophers, especially Jacques Derrida.

Others define the left and right as holding "collectivist" and "individualist" values, respectively.

But in making these assumptions, most of which aren't clear to the casual observer, theorists bake in their own beliefs. This undermines how useful (or otherwise) these models are.

https://www.miragenews.com/horseshoe-theory-debunked-far-left-and-far-1309878/

https://theconversation.com/horseshoe-theory-is-nonsense-the-far-right-and-far-left-have-little-in-common-77588