"It's natural that she should be angry." (sentence:248283, Core2000)
I asked a question about the preceding sentence's usage of も, and naruto explained the も serves to soften the sentence. I found the grammar explanation here, but still didn't quite understand も in this context.
I'm wondering, does も replace another particle here? How the sentence could make sense without も, if 怒るの stood alone without a particle. Would 彼女が怒るのに当然だ or 彼女が怒るのは当然だ make sense?