In many wargames, particularly in one-off scenarios, players march imaginary soldiers around a virtual battlefield don't care if they die. Morale is a mechanic to add a bit of versimilitude, but it often falls short in many gamers' eyes by not considering specifics of a situation and thus giving strange results. Most RL battles have 2 factors armchair generals often don't consider: the fact that there's actual people under command who don't want to die, and the fact that you need an effective force at the end or your victory will be undone by your inability to defend it.
Consider these situations:
A mother bear (or most other animals), protecting her cubs, ought to never fail a morale check.
Fanatical or highly motivated troops exist. Some of them on drugs, who don't even understand when they've been injured.
Highly trained and motivated troops who know what they can accomplish or feel their goals are critical to success and that success is worth the sacrifice.
People defending their homes and family.
People fighting a great evil or public menace.
A leader who has brought their troops through considerable adversity, who is working hard to do so again.
On the other hand, there are:
Poorly paid or unpaid troops forced into a fight against their will.
Barely trained or inadequately equipped troops. In WW1, some troops were sent to the front lines without weapons and told to take rifles from fallen allies.
People who feel their side of the war is unjustified.
On top of this, some game systems make it easier than others to safely disengage from a fight with an expectation of survival. And some gamers are quite bloodthirsty and will attempt to finish off retreating enemies. If enemies are not given the chance to retreat, of course they'll fight to the death - that's how it's going to go anyhow.
When I GM, I generally consider all morale situations unique, and ask myself what will the specific people do in each situation. Are they berserkers? Are they lost and at the wrong place at the wrong time? Generally this sort of analysis will make the decision clear.