If someone is willing to express their feelings and share their honest, outright feelings whether it's a friend, a client, or a colleague from work respect the fact that's how they feel.
We might think it's wrong or we disagree with their opinion but that is how they are feeling it's how they are experiencing the world right then.
The most important thing you can do is acknowledge how they feel and what they are feeling after all most people share something because they just want to get something off their chest.
That is a good place to start a conversation.
Just because you feel one way does not mean that "Everyone who experienced what you experienced should feel the same way."