I often use the word people to mean multiple persons. However, I’ve noticed that sometimes people will laugh/smirk when I use it. For example, one time I was talking about how my sister and her family/household travel often, saying, “Those people travel a lot,” and the person repeated those people and gave a slight laugh. I’m wondering if I may be giving some sort of unintentional implied message when I use that word.

Does the word people mean anything other than multiple persons, such as a group of persons united by a common identity (family, experience, nationality, ethnicity, etc.)?