This is nothing but a meaningless tautology. Of course there's middle ground, and one doesn't have to oppose something to not be in favor of it.
As an example: I like chocolate ice cream. You don't. That doesn't mean you are against chocolate ice cream, only that you personally disfavor it in preference to something else.
When someone makes a unilateral, non-negotiable, inflexible statement or demand in politics it usually means they are willing to use any means necessary--usually to include violence and repression--to get their way. That is definitely not a good thing.