Any soap will kill them if it's strong enough, it breaks down the surface tension of the water,the same as the class a foam carried on fire engines.
As for the fire dept "letting professionals" kill AHB , they have more resources to block off neighborhoods and area's to be able to soap down bees if needed,then a pest company.
If I had a mean hive or swarm going crazy at my house, and they have veils and are able to soap them down, I'd be glad to get the buggers killed.
I'm sure all florida pest would disagree, but FD's are everywhere,but pest companies that have any degree of bee knowledge or expertise are few and far between.
There's also a thing called public hazard and duty to act ,it's not to good of liability to leave the hazard for the public to get into,after a fire dept has left and not done anything to fix the problem.
As for the soap becoming a pesticide, to me that's a retarded example of big brother at work, or maybe a strong lobby by the pest control industry here ,I don't know.
Once your soap becomes a pesticide, then you have to have a license,go figure.
Where there are fruits and nuts there are beekeepers!!!