I'm sure not all people are that way. I would suggest it has a lot to do with the manner in which the information came up into conversation. I have reacted that way I admit but in hindsight I felt that reaction was part of the direction in which the conversation was already going. There have been plenty of other times where I have learned this of someone and it has completely passed me by.

What if you were to ask the individual(s) why they would assume such?