The credit thingy does work a tad differently: I only include direct reports.
It doesn't help me if players know about a bug, but don't tell me - because of that, I tend to only include players that reported to me directly.
In your case, Peridot and Tusimia could have reported the situation to me via /feedback, pm or forum reports - but they didn't. Only you did, and Dazz did. What fixed the bug wasn't some players being aware of the bug - it was - very specifically - your report and Dazz report that caused the issue to be fixed, nothing and no one else - hence those are the people I include. ;P
Hope that sheds some light on this. :3