Wrong. The premise of God allows a rational argument to be made for morality. The athiest has no premise that meets the same need. Further, the individual you talk to about God can be touched by God himself; the key premise is provable in his own experience, God willing. It is a relationship with God, not a set of rules, or a moral code, that is the key to life. Nonetheless, the premise of God allows the argument for morality to be made where no premise outside of God serves the purpose and is consonant with each individuals experience and reason. Doing harm to others often feels very good. Think of punching someone you are angry at, or exacting vengeance on someone that has done you wrong, or getting a young woman drunk and tricking her somehow into sex when she hopes for something more. Your argument from feeling sympathy for others fails, in my opinion.
You completely fail to understand. Feelings have nothing to do with it. I'll try to break it down.
The premise of God allows a rational argument to be made for morality.
I hardly think so. I used to think so, but changed my mind.
There are two possibilities:
I used to think 1 was the case. I found the Bible really supports 2. Consider homicide. We can give an exception for the case of self-defense, which seems reasonable (I would include execution of certain criminals under this category). But what about killing someone who has done no wrong to you or others? If we're arguing based upon God's unchanging character, God holds human life sacred and would abhor that as murder. But God ordered the Hebrews to invade Canaan and wipe out the Canaanites to the last child. They killed men, women, children, and babies. God would not order anyone to do anything that is evil, according to Christianity, so when God ordered the Hebrews to commit infanticide it must have been a good act, as blessed as feeding an orphan. This is completely at odds with the idea that morality comes from God's unchanging nature.
The other option is that what is good is what God considers good at that time. This removes much of the moral significance from sins against others because it strips from them their unchanging inherent rights--what right to life? Infanticide is no longer a sin against the person you kill and against God, it's just a sin against God because at that time it's his whim to consider infanticide wrong. Good and evil become just a checklist. The nature of God is unknowable, and possibly would be quite a surprise to his followers.
This situation is even worse than the situation of an atheist or agnostic, because at least the atheist or agnostic is free to accept as valid what they think is proper treatment of themselves. If it is wrong to murder only at some times and good and blessed to do so at others, then you cannot validly claim that there is a certain constant way that others should treat you. Humans become essentially worthless.
These two competing views of morality are in unspoken conflict in most forms of Christianity.
Even the most cursory observation indicates that the premise of God allows people to construct arguments for what they want to do anyway (e.g. "God says to kill the infidels"), without regard to morality.