Humanism doesn't mean humans are perfect. It means we're flawed but are capable of striving to improve. And it means that just because we have setbacks and failures, it doesn't negate the fact that we're capable of bettering ourselves. It means that even if individual humans fail, other humans can redeem them. Here, we had one human, Picard, pushed to the point of failure, but another human, Geordi, brought him back from the brink and kept him on the path toward betterment, and other humans including Riker and Hernandez helped bring about a triumph for humanity and its fellow sophonts over the ultimate anti-humanistic force.
So I'm with Thrawn. Destiny is very much a humanistic work.
The poster is Christopher L. Bennett, a Trek author. If you're interested in Trek books, he's one of the better authors I've read. He incorporates more science than the usual Trek author.