While I feel this person was mean-spirited with his words to the OP, I do get his train of thought. In normal apologetics when people are questioned about things like God-ordered killings the response is almost always how they were ultimately good. Our physical existences are considered a fleeting nothing when compared with the spiritual forever. Innocent people, especially children and babies, would suffer momentarily but would find paradise afterward. It’s an explanation that doesn’t sit well with a lot of people. When you take such an explanation to its logical conclusion, then any death (especially one of a believer in Jesus) should be far more celebrated than mourned.
One other factor to be considered is that often times if a person loses a loved one they will be told “it’s part of God’s plan” as if to say that supersedes the tragedy. Just like the Biblical killing rationalizations it often doesn’t sit well with non-believers, almost as if it is a devaluing of the life of the person who died.
This person who spoke to the OP, who again while inappropriate, has an incredibly valid point. This idea that the mortal life and the afterlife is everything – something that is spoken of constantly by Christians – has to be seen through all the way.