Your flag was declined with the reason "Use standard flags." Because you say two things:
- This isn't an answer
- The answer is evil and dangerous.
You're also dealing with a moderator who today hasn't had much sleep. I also was trying to do everything from a tablet so I can't easily open the entire question. You're right it was an evil command, but it's more "Not an Answer" because it doesn't even address the question being asked.
(I'm the mod who handled the flag by the way).
In my tired state, I was judging based on the "Not an Answer" state of the answer, not the command itself.
As was stated in comments though, it's usually best to make a comment to the effect that the command is dangerous rather than just rely on a moderator flag.
Comments are immediately posted. Mod flags take time for one of us to get up off our butts and sift through the flags queue.
You also should compare the actual answer to the actual question - the posted 'command', though dangerous, has no actual attempt to solve the underlying installation failure on the question you linked to.
Note that I did also delete that answer, but for the "Not an Answer" reason. my comments about the answer later on the deleted post were after-the-fact. (10k+ users and other mods can see that information directly)