system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why can we accidentally make bacteria resistant to antibiotics but we can't make ourselves bacteria resistant through a similar but opposite approach?

Over the last century (or so) we have made bacteria stronger and stronger via antibiotics. Why isnt there a plausible way to do the opposite by any means that isnt just letting evolution take its course? This may be a confusing question but I'll rephrase. Is there a way to kill *only* the strongest strain of bacteria and let the weaker (and less deadly) bacteria live? This would reduce the need for superpowered antibiotics and possibly(?) eliminate the need for them. Could we see bacterial infections so weak that we wouldnt even notice them?
gpt
The reason those bacteria became stronger is because they survived our best effort to kill them. We forced evolution's hand by eliminating the weak ones, and only the strong managed to survive. We already created superpowered antibiotics, and they resulted in super strong bacteria. The problem is that we have to make them strong enough to kill even the strongest bacteria, but not so strong that we kill the human cells at the same time.

Bacteria mutate much faster than humans can, since bacteria are ~~small and~~ relatively simple and reproduce far more rapidly than humans (i.e., mutations happen over generations, and bacterial generations are much faster than human generations). It's much easier for a simple organism to evolve than one as complex as a human. Also, consider the difficult position of defense. When you're on offense, all you have to do is find one way to beat your opponent. When you're on defense, you have to find all the ways to stop the attackers. It's much harder to build something that can defend against hundreds of different attack tactics than it is to find one really good attack strategy.

If we did manage to kill off all the strong bacteria, the weak ones would just mutate into stronger versions, and the cycle would repeat.

Edit: Added in the important stuff that Chel_of_the_sea caught me on.