With its latest abdication of common sense in the form of this new "helmet livery homologation," I think it's now safe to make the blanket assumption that F1 doesn't have the foggiest clue about how to run the sport effectively.
Helmet changes should not only be allowed but
encouraged. Why? Because every time a driver dons a new helmet, various media outlets around the world invariably publish dozens of photos of it, and the sponsors represented in the design get that much more (free) exposure, which both increases the value of the sponsorship and encourages new sponsors to join.
That fans (read: potential customers) tend to pay close attention to the drivers' helmets is the reason why teams put logos on them in the first place. This is not rocket surgery.
And don't forget: the chief reason why teams are required to run two different tire compounds during a race is to highlight the brand of the tires in the absence of a tire war. Such is the marketing power of heightened awareness, and these people should know better.
For a sport whose participants constantly bitch about costs, it's absolute lunacy to restrict the ways in which teams can potentially bring in more money.
/rant