The Special Collections Division of the Library of Congress is a two hundred year old organization.
They have told us they have an ongoing diplomatic relationship with the Catholic Church, and a formal liaison with the White Council. They have their own inhouse cabal of magic-users and magic crafters. They have demonstrated the institutional capacity to contain captured vampires, and are our primary candidate for the Feds that helped chase off the coven of lesser skinwalkers that got in a small war with a Native American tribe.
We dont even know what their relationship with the previous Dragon was; they certainly knew about the Red Court presence here, and if a newcomer like Arlene knew, so would they. And they were not surprised by the news of the Hellgate going critical either. I know Molly's convincing, but they werent about to arrange a meeting with POTUS to nuke Vegas on our word alone.
You are making one hell of a bunch of assumptions about who they are, and how they need our help to get set up.
Anyone who knew that gate was there would have been able to guess that something was going deeply wrong with it when the Chaos ritual went up, trouble is that most supernatural factions use Ways to get in and out of places fast and trying to get in and out of Vegas via the Ways during that rite would have been very bad for the health of most who might attempt it. Just about the only major player able to get in a car and deliver themselves the old fashioned way was Michael Carpenter in Chicago, but he was called to guard the Gates against a fresh attack
Molly could have pulled Ramirez in, but that is because she would have used her inner world to teleport-cheat, a kind of pseudo-Way though the soul of a nascent primordial no one could really plug up.