At worst you'd be offending thin-skinned crackers, but it's unlikely you'd even offend them if you're a cracker.
As a cracker: no. Only cringe losers give a fuck about being called cracker.
Edit: and if you're worried about offending Black people, I think you don't need to worry, considering the idea that slaves/Black Americans coined/popularized the term.
Whose house are you protesting outside of?