IMO once you get to a certain level within the FBI and other federal agency you have to have the correct political connections. You don’t reach such heights within our goverment bureaucracy unless you know and parrot the “right” people political ambitions.
I believe it was the reason it was kept out of hands of lower personal, not because it was presidential campaign and they had to be careful…but precisely that. They couldn’t risk it getting out (leaked) since lower levels of goverment personal/bureaucracy is slightly more political diverse.
You would more likely to have Trump supporters at the lower levels that might raised red flags…or worst bringing it to public attention.