I've experienced reactions similar to what you've described. Many, if not most people, really don't understand addiction. Most of my friends and family did not see me at my worst, so in their minds, I just need to "slow down", "pace myself" or "not overdo it". They see quitting for good as extreme and unnecessary. I could attempt to explain how bad things really were, but I honestly don't care to waste time doing so, and IMO attempting to explain my reasons for quitting is akin to justifying my decision, and I'm under no obligation to justify "not drinking".
These reactions, especially from family members, used to really bother me. I've had to learn to ignore their ignorance, let it go and move on. At the end of the day, I take pride in my sobriety and my ability to ignore ignorance.