b) because in many years of corporate experience, the vast majority of systems built with the intention of replacing Excel processes fail to achieve that goal.
It is true that knowledge workers are often disorganized and messy - in large part, because actual business is also messy and changes very quickly. When you start with the attitude of "unfucking" and "sheer amount of crap", it's obvious that you actually aren't respectful and aware of the actual day-to-day demands of business, their bosses, presentation requirements, messy input sources, etc. Pure, testable code may be more elegant but it simply is not as flexible and UI-friendly as Excel, which is a large part of why these types of projects fail at such a high rate.