@Iro-S-Boutique-Hotel0 Who explained that to you, perhaps forgot to take into consideration that life is a matter of degrees, not absolutes (aka 0/100 or 1/360, Black/White, etc).
What Airbnb is doing by those colors is letting you know, in a most simple bi-modal way, that once a price turns blue, by their computer logic, it is a price low enough that ~in all likelihood~ your place will get booked. Unfortunately, that price oftentimes is ridiculously too low, as also happens with most of their suggested prices in their 'Smart' Pricing program.
I would work backwards, and like @Roberta2 suggested, but put slightly another way - charge what you have to have to make your efforts worth it, otherwise why go through the exercise of hosting. Regardless of color.