I have no problem with every grace coming as a result of Christ's merits for the Christian. I was merely pointing out that God is gracious to all.
Except when He isn't!
There's a huge difference between common and saving grace. Plus you would have to reconcile your common grace-only rebuttal with numerous scriptures that teach He gives grace only to the humble. Humility is a spiritual/moral attribute whereas God's preservation of this world and the universe in order to sustain all life in this fallen world is not something He is morally required to do. He could have destroyed the heavens and the earth a lot sooner rather than later if he so willed it in eternity.