Ok I get he was cray, but at least demobilizing all zombies makes sense in a way since his failure to do it previously cost his son’s life.
But then he makes the jump to killing all living too, and kills them in a way that allows them to zombify.
So even the excuse of killing them to stop future zombies doesn’t make sense.
Morgan’s story is different in the comics. His beginning is basically the same. Like the show he is the first person Rick Meets after waking up. He was squatting in a house in Rick’s neighborhood with his son after losing his wife.
They spend some time together and separate, also like the show.
Then it changes. Rick returns to his town (the whole Morgan following Rick is not in the comics) and finds Morgan is is disheveled and erratic. His son had died and it has been a while since I read it but I believe he was feeding his Zombie son bodies (like the Governor kind of).
He joined Ricks group but he was twitchy, weird and suicidal. At one point he sleeps with Michonne and they have a relationship of sorts. This grounds him a little but he never really got over his son dying and he eventually gets bit and dies from the zombie bite.