I say again, you do NOT need the "to", sentences without it are also accepted.
You can also say "Není černobílé." when continuing an existing discussion about some neuter thing. "Jaké má to auto barvu?" Není černobílé." "What colour is that car?" "It is not black and white."
Otherwise use the common "je to"/"to je" to refer to any entity that has not et been established or is not a specific neuter object. E.g. to speaking about the present situation in general.
"It isn't black and white" is a perfectly fine and frequently used phrase. It means, essentially, that it is not that easy to make a clear-cut distinction. Here are a couple of examples showing the difference between being and not being "black and white":
"Love isn't always black and white, you know. You have to accept that there are many gray areas in relationships.
Don't debate me about it. The rules are black and white, and you broke them. "
Source: First entry at https://idioms.thefreedictionary.com/black+and+white