I did.
Grand Juries, as your experience demonstrates, are there to say "this is bullshit and there is no case" or "you've got a case, now let's see what the Petit Jury has to say about the defense rebuttal."
I think that theory leads to lynch mobs.
A grand jury is gathered by a prosecutor to make sure there's enough evidence for a jury trial. They are not gatherings of whoever decides to show up with a complaint.