You may be on to something with the raising of armies. The WC can't do that because they don't operate in the open. Harry does and may become something of a celebrity which could give him an even bigger following.
Only Marcone/Namshiel, Mab, Hades and Anna Valmont know that Harry has the knife. Nicodemus surely suspects it but only those four can say it with certainty.
Hey Mira, long time no talk, I hope you're well.
Well I agree this would raise even more concern but they have been worried about Harry for much longer, and for other reasons:
1. Son of Maggie, a dangerous wizard by all accounts. A real trouble maker.
2. He's a Starborn (It's hinted they are aware because Liberty telling McCoy "You know what he is")
So just being born, he was someone to be concerned about.
3. He killed (most think murdered) a Warden, and dangerous wizard.
Margaret Le Fey's Starborn son has killed before reaching adulthood, a great start.
4. He's open about being a wizard
We go to all this troube to be in secret and this man-child is practically announcing to the world we exist.
So by a very young age he was already a really big potentionally dangerous pain in the ass.
5. War with the Red Court
Wherever this man-child goes, destruction follows, and now he's started a war.
Imagine working incredibly hard to run a respected Police department, and one officer is raising hell, and leaving a trail of destruction. Before long people are making noise about this officer, and demanding you do something about him. This is Dresden. He's a member of the Council, and was a big trouble maker.
6. Warden of Demonreach
This was a huge one maybe the biggest... Dangerous, man-child, starborn is now in control of the prison that holds dark gods, and evil beings. At this point members were considering having him killed per words of Jim
7. Becomes Winter Knight of Mab
They want him gone, and now cannot do it without some serious wrath.
So from his birth he was a potential problem, and has only become more of one over the decades.
