Of course it's not normal for someone to say such an awful thing. What you have to keep in mind when you start to think it over is the context behind that phrase.
1. Who said it? Is it someone who's opinion you value? Is it someone that's important to you? If not perhaps you it's not worth your time to even consider it.
2. When did they say it? Do you know what's going on in their life? People tend to say many things they regret during times of hardship and stress.
3. How did they say it? Was it out of anger or sadness? Did they say it as a joke? Make sure to find the underlying reason as it could help determine if they mean it or not.
4. Where did they say it? Was it in a social context or was it in private? People tend to act differently depending on their environment and can say they things in a group that they would otherwise never tell you out of respect.
5. Why did they say it? Did you have an argument with this person? Did you say negative things about them prior to this? Arguments can escalate tensions turning a discussion into a battle of insults.
Remember the context is everything :)
Did you find this post helpful?
Related Questions: Is it normal for someone to say why do I even exist?