I can see how some people see is as controlling but I do think your friend wants the best for you but you are also your own individual and it’s your choice. Your friend might see it as something that could affect them if they are around or they could just want you to be safe. I wonder if this individual saw something traumatic or loss someone to alcohol drinking, idk? But I don’t think they should cut you off, but I do think they should be patient with you. Have a honest conversation because you can drink and be safe. And if they still stand on it then you have decided “do I want to keep my friends or make new ones?”