People will say a lot of things to try to get you to not suicide. Possibly your friend was so devastated at the thought of losing you that he/she blurted out this unhelpful thing. Also, I have seen it in print that suicide is selfish, so I think there are people out there with that opinion. As in, you would be out of your pain, but they would be in terrible pain. Suicide does really hurt the people you leave behind. And for many people, the thought of the hurt that their death would cause is enough to keep them safe.
Can you take it as your friend was saying that they would really grieve?