But none of that came up in the trial, none at all! The only thing that mattered was that I didn't have permission to access a URL that I accessed. End of story. Intent doesn't matter, the fact that they sent it to you doesn't matter, all that matters is that you accessed it purposefully, which you did.

If you had seen the page, and reported to the proper authority that there was a serious security flaw with the system, you would never have been tried for anything illegal.

Funny you should mention that, because there have been hundreds of people charged with crimes under the CFAA for doing just that. It's why security researchers are encouraged to hire a lawyer before revealing vulnerabilities, because companies often respond with lawsuits and people can have their lives ruined because of it.