A buyer asking for closing costs is the same as a buyer asking for a discount. In reality, what they are asking is for them to be able to finance the closing costs by keeping the price that much higher instead of asking for an equal discount.
The question I ask my seller's when this comes up is are you willing to sell the home for the "net" price or not? If the list price is $250,000 and the buyer offers $245,000 and wants $5000 in closing costs to be paid by the seller, it's almost the same as the buyer offering $240,000. If in this example, $240,000 is an acceptable price, consider accepting the offer. You can also counter back at $255,000 with $5000 in closing costs, which is equal to your list price. The only issue with this counter is whether the home will appraise for the $255,000 price; if it does, then you get your list price, the buyer gets to finance the closing costs and everyone is happy.
Because VA is a 0 down program, buyers with very little liquid cash try this to hold onto what they have for savings or moving expenses, but buyer's of all types of loans may request this. It's just another way of receiving a discount to them.