If something-- a sermon, a book, a person-- proposes to be Christian, it had better actually be about Christ, right? If someone talks about God, which God are they talking about? He had better specify.
Christians should never talk about God without mentioning Jesus. Without Jesus, God the Father is completely inaccessible to us men. God the Father, apart from Christ is for us as in the days of the Israelites wandering in the desert, camped at the foot of Sinai. This was a mountain they could not touch, could not approach, without death coming surely and swiftly upon them.
"God talk" is nothing unless it's about Christ crucified for sinners.
Also, talking about God and His righteous demands, without talking about Christ's fulfillment of them has nothing to distinguish it as Christianity from Judaism, Islam, Mormonism, and a host of deist and theist cults.
Paul resolved to know nothing but Christ and him crucified when he was with the Corinthians. Why don't we Christians do the same?