55 vs 75 no difference?

Yeah if you think a 75mph crash will kill you but you get to walk away unharmed from a 55MPH crash, I have really bad news for you.

speeding cause less wrecks than driving 'slowly' in the left lane?

That is correct. Speeding is involved in a minority of accidents, and is the cause of even less. Over the course of a decade, I’ve seen two fatalities due to speeding, they didn’t harm anyone but themselves in the process, and both were on residential boulevards, not the freeway. I’ve seen far more caused by erratic unpredictable driving, driving too slow for traffic, and turning into traffic.

I’m a man who’s been fortunate enough to have saved dozens of lives that were almost ended by people like you that become road hazards on purpose, and less fortunately the witness of far more innocent people losing their lives because of drivers like yourself. People like you have caused far more injury and death than any speeders could hope to. Speeders are nothing more than a convenient scapegoat. As long as they themselves are not driving erratically or switching lanes unpredictably, they’re of minuscule concern. There are countries with freeways that have speed limits more than twice the U.S. and they do just fine.

the fact that fatality rates on German motorways that don't have a speed limit are 76% higher compared to the ones that do

A very clever misrepresentation of the data, I’ll give you that. While it’s true that if you get into an accident on a non-limited section of the autobahn , your odds of the accident being more severe or even fatal are relatively higher than it being a minor accident. However what you’re very strategically leaving out is that your odds of getting into an accident in the first place are lower on non-limited sections of the Autobahn.l, with some outliers based on rarity of the various speed limits. The most common speed limit on the autobahn being 120 (substantially higher than the average speeder in the U.S.). Here’s some data from a 2022 study on the effects of speed limits and their effect on accident frequency on Autobahn. It lists several different speed limits and crash results, with the primary comparison being between 120 and none. With the other speed limits being rarer outliers.

TL;DR It’s not that severe accidents happen more often on non-limited sections of the autobahn, it’s just that the smaller amount of accidents that do happen are more likely to be severe. It’s hard to compare these results to accidents caused by traffic impedes, because as previously mentioned that’s a particular problem that Germany seems to have eliminated. An argument could be made that it’s be a prudent decision to add a 120 speed limit to the rest of the autobahn, and trade a higher accident rate for fewer fatalities, but that’s a luxury that Germany has because they’re not dealing with more dangerous behavior like in the U.S, such as uneducated, unpredictable, and slow drivers impeding the flow of traffic.

I know you want what you’re saying to be true, but you’re wasting a lot of energy that you could spend on becoming a safer driver instead. Take all this effort you’re making to find numbers that almost look like they’re supporting what you’re saying, and put it into learning about your states driving laws instead. I’ve at this point put a lot of good faith effort in educating you, but I’m not going to continue poking holes in the logic of your responses.