The issue is not so much about motive, even kindness vs. selfishness. It is about how we all do this little mental dance of justifying our actions, thoughts and feelings. One of my often repeated questions has become, "What are you defending?" I can speak for no one else, but I personally grew up in a household where I was always on the defense. I have been taught how to do something different. The assertiveness has replaced the defensiveness, but not before a period of somewhat unreasonable selfishness. For me, this represented a risk in order to know myself and my boundaries. It has been said that the truth is always in the middle, as the Buddha espoused the middle way. Ultimately, we all get to take our share of life and experience, and nothing is free. We pay for it all and we deserve the best. For myself, recognizing that my defensiveness was based on low self-esteem, was the beginning of a journey toward personal growth. Just some random rambling.
Back to the ice cream cone. The issue is not about the response. The issue IS the motive behind the response. Consider this. YOU are now the one asking the questions. That is your responsibility to your self. It is the responsibility of others to answer or decline compliance. It is about exercising the freedom to be and do what is consistent with your nature. It is about having the courage to explore who and what you are, truly. This has been my journey. All my opinion of course. I do not have to be a nice person, I choose to be that, most of the time. For me, there IS a big difference.