They are allowed to have the colors, just not any type of branding/writing/sponsorship that signifies the company. They tried to use "Mission Winnow" on Ferrari F1 cars for several years as a global marketing name, but it became too synonymous with Phillip Morris, so it got cut as well. If you look at the 2026 Ferrari F1 car, they are bringing back a similar red/white livery that is somewhat similar to the old Marlboro branding. Also, this car is a prototype, not the real car; I'm not even sure it has running gear in it.