Mostly I found the post tl;dr, but I'd like to note two things:
1) Yeah, you're somewhat right in theory,
2) But, no, this doesn't matter in the long run.
This is because the advance of technology is moving in exponential inverse proportion to the dilution of the human gene pool. The more we advance technologically, the less the lack of evolutionary rigor will matter.
Take me, for instance. I have and have suffered from chronic asthma, a hernia, appendicitis, ingrown toenails, impacted wisdom teeth, and a variety of colds and flus. Every one of those things would have killed me in a state of nature and, without the advances of modern technology, most of you would probably be already dead at your ages from similar circumstances. Regardless, I believe that most of us deserve to live despite our physical frailties, myself in particular
Your argument, in essence, is the basis for the philosophy of genocidal white supremacy which lead to Nazism and, on a less horrifying note (depending on your philosophy), to the pro-choice movement. Take it easy, the world isn't all that grim; think of it less as the absence of natural selection and more as the shift of the emphasis of natural selection from the absence of physical weakness to the primacy of social and intellectual skill. In other words, evolution isn't controlling us now by rewarding us with genetic immortality for not dying but rather by getting us laid when we do awesome things (hint: we call it capitalism).
In a few decades, technology will turn us all into Nietzschean ubermenschen as far as our physical bodies are concerned. The next level of evolution will not be physical, it will be psychological: it will be involved in getting us to use our nanotech-enhanced super-brains to do something other than sitting around the house pounding away at our portable blowjob dispensers.