actually if you go back and reread bz talked more than white zetsu.BZ never did talk much though, it was all white zetzu.
Let him talk, you can't do shii about it.
He was talking too much **** because his dear mother was there, but hey at least he's gonna get soloed by Naruto next week.
He hid behind Madara as well,BZ had to stay attached to Obito because he was scarred shitless of Minato,Gaara,and Kakashi.
The irony is powerful with Zetsu he calls Obiyo a parasite, but he is the one who back stabs and hides behind others to survive.