12c: Bypassing EM to turn off metric thresholds

File this one under the heading "not quite sure why this exists" as the article "How Disable Database Time Spent Waiting (%) At Database Level" on MOS with note 1629021.1 clearly explains the commands to turn the thresholds off for several different types of wait classes, but I do not understand WHY this is an option, required, or even suggested.  Is there a bug in the 12c EM which requires this to be completed "by hand"?  If there was a problem, I could understand turning off some threshold alerting but this seems completely backwards to anybody wanting to be proactive.