Former Uber CEO Travis Kalanick has absorbed blistering criticism for the way he handled allegations of sexual misconduct at the San Francisco riding-hailing service. Speaking at the annual Stanford Directors’ College Tuesday, Mayer defended Kalanick, suggesting that he was unaware of the toxic culture brewing at Uber because of the company’s rapid growth. Mayer’s defense of Kalanick might seem strange given her iconic status as the rare female chief executive in the male-dominated world of technology. The beleaguered ride-hailing company has said it will implement 47 sweeping recommendations from former U.S. Attorney General Eric Holder, whom it hired to investigate allegations of sexism, bullying, retaliation and other workplace issues. Holder’s report acknowledged the catalyst: a blockbuster blog post from former engineer Susan Fowler in February detailing hostility toward women at Uber’s San Francisco headquarters — and her futile attempts to get managers to respond. […] Uber has been mired in other controversies: a trade-secrets lawsuit, a program to evade law enforcement, an engineer’s suicide and a video of its CEO berating a driver.