Your anti-gun bleating not withstanding, just stop making crap up as you go along. "Brandishing" would actually require blatantly displaying the gun, most definitions actually require it being removed from the holster or purposefully shown in an attempt to intimidate.
Not the case here.
Not being a LEO in Washington, I can't even begin to guess why the caller was not ID'd. Since you seem to be good at pulling facts out of your hat, why don't you make something up and post it as fact to explain this....
And no. I don't think they should have their permits yanked. If there was a citable offense that had taken place, they would have been cited before being released from the police station. If anything, I think it is a travesty that permits are even required. I am a full 2A advocate and feel that Alaska style carry laws are the ONLY ones that a even remotely Constitutional.
We will have to agree to disagree then. Unless you were there, neither of us KNOW whether it was purposefully shown in an attempt to intimidate. Barring any further information to the contrary, however, I will side with the police on this one. Also, I think YOU are the one assuming it was an "anonymous" caller - from the story, it seems that the police know exactly who it is - at least enough to know he / she was "not part of the march".