They just couldn't let him get near clients. Because it's unarticulated, the new khaki-nation uniform is able to enforce a number of biases quite invisibly. For example, super-clean casual dress is much more complicated for women than for men. For men, slapping on a pair of khakis and a funky shirt is just a way of looking harmless. The whole point of business dress was to sort of downplay women's sexuality, by aping men's clothing.
Casual dress changes all that.
Even female geeks, the programmers who are supposedly valued only for their skill, feel torn. If you wear typical programmer clothing, you don't look feminine, which freaks some people out. Even more cynically, the tropes of hipster down-dressing savagely exclude anyone older than, say, forty. I know guys who can code circles around anybody. But if they walk into a job interview in Silicon Valley and they've got gray hair and they're not dressed like kids - it's over.