"everyone reacts differently to things" is ambiguous. It can be supportive or invalidating depending on the context. If it’s used to defend someone’s reaction as understandable even though it’s not how others react, it’s supportive. If it’s used to minimize pain as if it’s not worthy of consideration, then it’s invalidating.

And when something that is ambiguous comes from someone who’s not familiar, and there isn’t a lot of context, its often the case people project their own experiences onto the ambiguous statement as to determine if it’s positive or negative. And the potential reason why people with cptsd arent as likely to say things like that is maybe because cptsd often makes people more aware of how things can come off negatively to those with trauma so they do more to avoid ambiguous statements.