1. Someone hasn't read the book and only glanced at the title.
2. That someone assumes the book says "test things on your mom, because there's nobody less tech-savvy than an older woman, yo momma so dumb she thinks a hamburger menu is something you get at McDonalds"
3. That someone, hoping to be an ally in the fight against gender and age discrimination in tech, takes offence at what they imagine the book says.
4. A mob of people who also haven't read the book destroy your career.
Of course, we've got like 4 levels of hypothetical here - you're reading me, putting words into hbeckpdx's mouth, who is imagining an easily offended third party, who is imagining the contents of the book, which they imagine is offensive to a hypothetical mom. Whether you agree with hbeckpdx that this is a reasonable thing to fear is another question....