The same reason older people vote the most, I’m sure: older (retired) people are more likely to have the free time.
I got the same kind of “is there a problem?” reaction, and I was only in there for three to five minutes. There were very few races in my area this year - president, four judges (all unopposed, so I didn’t bother voting for them), a representative, an assembly race and I think a council member… and this is New York, where people start grumbling pretty fast. Sorry, people in line, I actually took the time to read the ballot initiative, too. 