1. People are capable of both great evil and great good (often in close proximity).
2. Having a great intellect may, in fact, make someone more compassionate.
3. Finding meaning in a cause, project, person, etc. can allow a person to endure much more than most would expect.
For those who aren't familiar with Frankl's personal background, you'll find many of the relevant details in that book (and perhaps also in the linked video although I haven't finished it yet). Trust me when I say that the man has a legitimate claim to discuss the topics on which he tends to focus.