SPOILERS AHEAD
A character that has been built up and established as honourable and morally good should never die a dishonourable death. The issue that people have is that Joel was brutally murdered, as if a lamb dressed for slaughter. There is no honour in death outside of a battle or selfless act. If Joel’s death would’ve come as a sacrifice, NOBODY would’ve had a problem with it.
Bare with me, but in Norse mythology a death occurring in battle is regarded as a great sacrifice, and thus the soul reaches eternal life in heaven. A death like Joel’s awards no satisfaction other than a cheap plot device to drive Ellie forward.