The unconcerned reaction is my way of telling them, in a nice way, that they have not earned the right to force their way into my memories. I suspect that they want to hear my stories for the entertainment value only. And until I decide that person is worthy of hearing my personal reminisces, there will be silence from me.
I suspect these older veterans are the same as me.
I might point out that 3 out of 4 of my interviewees came to me first. When I began started researching my dissertation, I put out a call through contacts that I wanted to talk to veterans of the Big One. I received over 2,000 replies, but was constrained by time, topic, and money in whom I could talk to. I ended up with less than 150 completions, in total.
Still, my 40 years of WWII research has left me honestly humbled and grateful for the service of all veterans.
(As a caveat, I should point out that I was turned down by the Navy at 19 because of a minor heart problem, which has given me no trouble at all. I feel kind of cheated, still.)