Your friend is not wrong but they were still being toolish about it. You mentioned your struggle, your problem; and instead of trying to commiserate they basically said "it could be worse". Know how you feel, most people can't relate with my life experiences either so in the past when trying to discuss them I received similar levels of dismissal. Something I realized though is that it goes both ways: in the moment they said " that's your privilege talking", you had a window to turn the conversation back to them, to ask about their experiences. Of course that direction for a convo isn't always appropriate, or it may be asked too awkwardly to get a thoughtful response, but I will mention those times I shut up and opened my ears were some that broadened my perspective the most.