It is an imprint, but a small one. That doesn't negate my point - just because its a part of a larger company that doesn't mean its still small, especially in comparison to where it was originally going to be published. It was going to be published by Simon and Schuster themselves, the flagship name.
No it wasn't. The cached version of the book's page on Simon & Schuster's website (the one you yourself linked to) indicates that it was going to be published under the Touchstone imprint. How big is Touchstone? It's so small that it uses its small size as a selling point. From their website: "We are a publishing boutique imprint backed by the publishing power of Simon & Schuster. Our small size means we only take projects that speak to us on a meaningful level."
Calling it a feminist focused print company may not have been accurate, but it is certainly focused on social justice issues and comes from a left-wing perspective. Simon and Schuster is a-political, so the book won't be aimed at a mainstream audience.
It's not focused on social justice issues, though. One of the titles currently on their main rotating banner is a history of champagne. I've already pointed to one of their recent books about the relationship different presidents have had with the intelligence community written by the CIA official who handled briefings for Clinton and Bush. Another title includes a book on the rise of Putin by Garry Kasparov.
I don't have the time to dig through all of their books, though. The publishing industry as a whole tilts left (there's a reason conservatives start their own publishing companies), so I have no doubt they publish a lot of liberal and left-wing projects. However, poking around on their website, it doesn't seem accurate to say that they focus on social justice issues.
Yes, but a imprint is a smaller section of a larger company, whose focus is on a different market. This particular market is small, its not mainstream. PublicAffairs for perspective only has about 1,600 Facebook likes. For comparison, Simon and Schuster has 115,000.
However, Touchstone, the imprint that Quinn's book was originally going to be carried on, has about 3,200 likes. (I'm not sure that Facebook likes are meaningful measures of anything, since there are so many factors involved in how many likes an organization gets that have nothing to do with size.)
Anyway, what you don't seem to understand is that publishing companies are collections of imprints these days. That's how they operate. Even Stephen King, one of the best selling English language authors of all time, is published on an imprint: Scribner, an imprint of Simon & Schuster. It's just how the industry works.