Are detailed style requirements inappropriate from Marketing?

Question

I'm working on the UI-side of a project which is under intense scrutiny by our Marketing group. Most of the time, we're reviewing functionality requirements.

Once in a while, however, they will get very in-depth regarding colors, styles, etc. For example, I've been tasked by Marketing to make one particular button a very specific color and a very specific size,

In other projects I've worked on, however, these types of requirements have been quietly ignored or rejected when they came from Marketing. Managers and tech leads have insisted Marketing shouldn't be specifying details like colors, styles, control layouts, etc., but I've never really been told why.

Is it inappropriate for Marketing to list detailed style requirements for a UI, including colors, shades, layout, sizes, etc.? If so, why? Is this just a case of conflicting philosophies regarding Marketing responsibilities?

(I should probably mention that we're not working with a unified style guide for company-wide applications. In the past, other projects I've worked on have "winged it" when assembling their UIs.)

---

Edit: I removed an editorial comment I made which probably implied this post was a complaint couched in a question. I'm not really concerned with what I should do, but rather I would like better understanding as to what Marketing's responsibility is regarding these types of requirements. I've had very little exposure to Marketing (I've been more distanced from them in previous projects) and I don't understand their role as it pertains to UI styling.