It may be worth pointing out that legal justice is really a
post facto affair. The question is not whether bad things sometimes happen in the US, but how the legal system reacts to it after the fact.
In both the cases you've cited, the book is far from closed on the incidents. It's hardly even opened.
To establish anecdotal evidence of real injustice, you need to cite cases where the legal system failed to provide any sort of redress. Which with more effort you certainly could; I'm not claiming otherwise, nor am I claiming that you can't build a more comprehensive fact-based case against the US on some grounds. My point is simply that the implicit standard you are using by citing two things that haven't been through the system can't be used to score points for or against the system yet. The question is less "can you be put in jail" than "can you be kept in jail", and the corresponding second-order effects that has on society.
I am not entirely satisfied with the US; I am simultaneously not aware of any place that strikes me as obviously better, or even obviously on a better long-term trajectory. (Some places are better in some ways but end up being worse than others.)