You know unfortunately for some it comes down to they need a case to have zero doubt at all. Not "reasonable" doubt, but none.
So for most people, when you have, for example, forensic evidence and witness testimony indicating someone asked another person on three separate occasions, to murder the mother of their child, and then had text conversations back and forth with the mother setting up a thanksgiving celebration, but then the celebration never happens, mom appears to have prepared for the celebration, goes to the store to buy supplies for a dish she's planning to take to the celebration, but she is last seen at that store the same day and is never seen again, neighbors see the father's truck at her house shortly after or around the time she was at the store, he ends up with the baby she brought to the store, but mom never shows up as planned, he tells everyone DAYS after she is last seen that they broke up and she left the baby and took off, he never reports her missing even though he's had no contact with her for an unprecedented time while he has their child, her phone pings and sends texts in the same state a suspect lives, who later admits to having been solicited to kill or help kill the missing mother, and whose phone data shows evidence she assisted the father, and there is blood evidence or other evidence of trauma and great bodily injury in the house, for most of us, that would lead us to find it reasonable to conclude that the mother was killed on the last date she was seen alive.
It's logic. But sadly not everyone is logical.