I was thinking that it was because DC is more swampy liberal.
Location matters in my opinion. Is it true? Dunno. 
You're talking 20-ish
voters from last election, 15 jurors and 5 alternates, chosen randomly by computer... and are
sworn-in. No discussion about any of the evidence between presentations, nor at any other time... No discussions 'outside' the jury-room with friends and family-members. Forever.
Mueller & his peeps won't present one version of
a count. It'll be
Felony Obstruction 1-A, 2-A. 1-B, etc...
Misdemeanor Obstruction 1-A, 2-B...
Mishandling of...
on down to the lowest...
Then the Clerk calls out your name to rate what the evidence should be charged as.
It never needs to unanimous in a Grand Jury.
So yeah, there could possibly be 15 Trump-hating Hilary-voters in the room. But it'll become pretty damn obvious there's
jury-misconduct afoot if every charge is the maximum for every piece of evidence. If Mueller wants to risk ignoring the misconduct, versus
the passage of time spent, he has only himself to blame for the eventual pro-Trump insurrection which will begin breaking-out across the Republic.
Starting with shutting-down the Interstate Highways into DC. Then the rails. So c'mon, Bob. Bring it.