First published in 1995, so the most recent person in this chronological listing of history-shapers is Oprah Winfrey, born in 1954. So that means no Barack Obama.
It's a good book, it has 100 one-page bios of important folks, there's a lot of bang for the buck. But besides Bayard Rustin and James Baldwin, I spot no other LGBTQ+ people. I think if you were writing this book now (and plenty of people are) you'd include Audre Lorde, Marsha P. Johnson, Pauli Murray, Barbara Jordan (never out), or Angela Davis. I mean at LEAST Angela Davis. And you'd probably also include a couple more people who were labeled 'radical' at the time - Bobby Seale, Eldridge Cleaver, Stokely Carmichael.
And in the end... no Barack Obama.