I was forced to give out my name during an unsolicited introduction at the gym

Out of nowhere, a guy at the gym introduced himself (Eric). I didn't know what to say, so I nodded with a smile. He then asked me my name which I hate because I don't want people who I don't know calling me out. I felt I had no choice, so I told him, but now this is the second person at the gym who has forced me into giving him my name. At this rate, it's going to be overwhelming trying to avoid all these people who know my name.

He then said, "By standing behind that bench, people can't see your ass." Once again in the same conversation, I had no idea what to say so I didn't say anything. He kind of stared at me and smiled but when I just stood there, he turned away. We both went back to working out and when he went to put away his weights, I quickly left that area.