Well, you do, but not if you don't already find their views palatable.

There is a large undercurrent of reactionary hateful views in German politics that usually hides behind the fig leaf of "conservatism" but has become more visible thanks to parties like CSU openly copying AfD talking points and "liberal" media being unequipped to handle them in any other way than giving them a platform and hoping that the "marketplace of ideas" saves the day. Of course as we now know from experience, "rational debate" is impotent in a "post-truth" environment.

It's a widespread misconception that Germany got rid of all the Nazis and Nazi ideology during the so-called "Denazification" (Entnazifizierung).

While there were formal reviews of the innumerable former NSDAP members to determine their ideology and behavior under Nazi rule, only the most blatant offenders faced any consequences and it was demonstrably easy to "cheat" (i.e. we now know based on a better understanding of historical records that some people were able to hide very incriminating evidence of their involvement in e.g. forced labor and Jewish persecution) and any undesirable rulings could be appealed to offer another opportunity to "correct the record" so to say. As a consequence, many Nazis saw no real consequences and even ended up in the same positions of power because their job experience made them the most qualified (and "innocent until proven guilty", right?).

Additionally, many former NSDAP members went on to continue working in politics. Of the parties still relevant today, the conservative CDU/CSU received the lions share of them, in addition to those formerly associated with the likewise Christian "center party" which while ostensibly "politically moderate" was one of the driving forces in the rise of the NSDAP and the passing of the Enabling Act dissolving the democracy.

In East Germany, likewise many former NSDAP members ended up in the equivalent of the CDU/CSU (known as CDU in East Germany at the time and CDUD or Ost-CDU in West Germany), the NDPD and the LDPD (the East Germany equivalents of the market liberal West German FDP, the NDPD explicitly being created to target "unimpacted" ex-NSDAP members and siphon off conservative voters who would otherwise have supported the CDU or LPDP), all of which continued to exist as an executive organ[1] of the ruling unity party until 1989.

It's also worth pointing out the East Germany was even less rigurous in its "Denazification" (Stalin ended the program in 1948 insisting that it was time to stop distinguishing between ex-NSDAP and non-NSDAP and instead focus on growing democracy) and the SED was uniquely ill-equipped to deal with neo-Nazis when they arose, previously already having viewed "unimpacted" NSDAP members as politically confused rather than genuinely dangerous. For some it was literally impossible to imagine neo-Nazis could exist in East Germany because they saw the rise of the Nazis as a response to capitalism and East Germany was supposed to be non-capitalist[2]. For this reason, East Germany was however (like the USSR) quite successful at fighting other leftist currents, which were seen as misguided or even "capitalist" (as the only valid form of anti-capitalism was clearly that practiced by the government and opposing it therefore must be capitalist).

So in essence Germany has never weaned itself off fascism, really. While Germany has become generally more progressive compared to the 1930s, in some ways it is also still less progressive than it was during the Weimar era. A lot of leftist politics also died even before the suppression under the Nazis, the suppression under the SED or the suppression under the Cold War era anti-communist West Germany: while many know about the in-fighting between the SPD and the USPD after WW1, culminating in a massacre at the hands of monarchist paramilitaries, there were also numerous other leftist mass deaths such as the two(!) socialist republics in Bavaria, which eventually also fell victim to the monarchists.

In other words, it shouldn't be surprising that we still have monarchist terrorist groups (Reichsbürger) treated with more bewilderment than horror, whereas the closest we have to leftist activism is moderates gluing themselves to public roads to demand incremental climate protection legislation, and two so-called leftist parties that hate each others guts and one of which has almost fully embraced neoliberalism (the SPD implemented the neoliberal reforms of weakening labor protections, social welfare and medical care some 20 years ago).

The AfD is a protest vote in as much as Trump is a protest vote. They're not something you usually bring up in polite conversation but they have easy answers and push all the right (wing) faux-populist buttons.

[1]: Point of pedantry: East Germany quickly established a system with a single ruling party, the SED or "socialist unity party". However the CDU, NDPD and LDPD continued to exist as "block parties" and began increasingly aligning themselves with the ruling SED. The "block parties" were infamously nepotistic and provided a relatively easy path to political power and privileges compared to the dominant SED.

[2]: Point of pedantry: East Germany was not "communist" although it was at times framed as "Stalinist". East Germany instead eventually used the label "real existing socialism" (along with some other Eastern block countries) which was intended to frame anyone left of the ruling party as "utopian" and unserious. This "it's already as good as it gets" position is distinct from other so-called "communist" countries which often used the term aspirationally, claiming they would eventually achieve the communist ideal after reaching a tipping point (allowing the state to "wither away"). Both are distinct from anarcho-communists who would argue that if you try to build a state to achieve communism, "real existing socialism" really is the best you can hope for because states don't wither away voluntarily and you can only grow communism from the ground up (cf. prefigurativism).