Why is the subjunctive used in one sentence but not the other?

Why is the subjunctive used in one sentence but not the other?
 

From a reading, I have the following sentences:


"En la sala de estar de la casa, pusimos un altar, un lugar para pensar en las personas que han muerto."

"En las casas ponemos altares para alguien de la familia que haya muerto."


I figured the subjunctive was used in the second sentence because they aren't talking about anyone specific, so aren't referring to any actual death. But then I feel like that should apply to the first sentence as well. I suspect maybe the different sentence structure of the first sentence has something to do with it but I'm not sure.

The subjunctive is used to talk about something that hasn't happened yet. This is what is being communicated in the second sentence.

In the first sentence, both actions already occurred.