Earlier quoted context omitted.
So his issue was not that you discovered the bug. His issue was that after discovering it, you went on to view a bunch of other people's data. What you did was walk down the block, pull on the doors of random houses, and if you found one unlocked, went in and took a look around. If you found my door unlocked and left me a note, I would be grateful. If you went in and took a look around, then did it to all of my neigh…
This was not an "unlocked door". This was going to the doctor's office, and while sitting in the room with your files, seeing a bunch of other patient files just left on the desk in eyesight. Not in an unlocked filing cabinet, not in an envelope, but in the open. Changing a URL is not "malicious use" nor is it considered doing something you're not supposed to. As a web client, I should be able to change or manipulate…
the law disagrees
as far as your doctor's office strawman - it's a strawman. To see those files, you don't have to actively do anything, if they are left at the desk. Now, if you pick up one of those closed folders, open it, then start looking through it - you have an equivalent comparison. You also have an arrest record.
But don't argue with me. What he did is literally illegal.