The gamifying started immediately.
If you ever make anything competitive there will be that one guy trying to cheat his way to the top.
The high score list was supposed to be for finding logic errors. This guy was trying to pass off finding typos in text strings as equivalent to finding something that would blow up prod if pushed up.
I really... hate... reality
But more seriously, while this is worded as a result of abuse, it had been up for more than a year at this point as a way to push people to use Kiro (you get badges for each "level" basically). Once you reach a point where everyone is using those tools, it makes no sense to keep it around.
Also it was not related to any performance metric, it was a pure vanity thing of getting virtual awards to display.