There is this book, called "The Five Love Langages".
"Unhappiness in relationships often has a simple root cause: we speak different love languages, believes Dr. Gary Chapman. While working as a marriage counselor for more than 30 years, he identified five love languages: Words of Affirmation, Quality Time, Receiving Gifts, Acts of Service, and Physical Touch. In a friendly, often humorous style, he unpacks each one. Some husbands or wives may crave focused attention; another needs regular praise. Gifts are highly important to one spouse, while another sees fixing a leaky faucet, ironing a shirt, or cooking a meal as filling their "love tank." Some partners might find physical touch makes them feel valued: holding hands, giving back rubs, and sexual contact. "
So there are some people who's Love Language is receiveing gifts. So by telling them you won't exchange gifts, you are effectively saying you don't like them anymore. That may not be your language, but it very well might be your BFs GF's.