Yes, I know what truculence means, thank you very much. What I don't understand is how it makes grammatical sense in the sentence Angelou wrote. I think she meant the walls' truculent refusal to fall down. But as written, the sentence is ungrammatical. I can forgive the Washington Post's editors allowing Angelou's pretentiousness, self-righteousness and lame, exhausted metaphors into their paper. (Joshua? Please.) But I draw the line at patently bad grammar.