Here's the following events of what he did in the 2000's. When he was reborn via Techno organic virus he creates new Horsemen, comes to the X-Mansion making famine use their powers to weaken the X-men so they'll take his blood as an antidote and make him a mutant messiah. After that he confronts the leaders at the United Nations with an ultimatum: he'll destroy 90% of the world's population, ensuring humanity and mutants are on equal terms to fight for the survival of the fittest or he'll unleash a plague which will destroy humanity.
In the "Heroic Age" versions of Apocalypse and the Four Horsemen attack Avengers Tower when Kang breaks time. Fantomex clones him into a teenager to be raised in the X-men's Academy (Evan), during the "AXIS" storyline he's aged to adulthood he leads an uprising of mutants against Avengers Tower, to detonate a Celestial-based Gene-bomb to wipe out every human on Earth and is only stopped by Carnage sacrificing himself. Deadpool convinces Evan to stop by saying that everyone liked Evan and hated Apocalypse and the two ran away together.
The "Apocalypse Wars" had the X-men travel thousands of years into the future finding a destroyed New York City, where Apocalypse had conquered the world. It worked like this: those who survived certain trials lived under his rule and it was a world tied to his health with the Four Horseman acting as his "antibodies."
After that his body degenerated and he put his consciousness into human hosts, he got to his fourth, and he becomes fully human in the process. When he found the perfect host he killed the rest of the human test subjects and destroyed the island he was on which had been altered by is experiments.
What people aren't understanding about Apocalypse is that he's not a modern terrorist or criminal he's from a much older, primitive lens where all that mattered was domination and death. Don't think of him in terms of modern philosophy or culture, and he's shown he hasn't regressed in these stances, like human sacrifices, gladiator bouts and cult indoctrination. The Crucible shows he still continues these beliefs.
I haven't gone into what he was doing before all this.
You want me to trust this person with the future of mutant kind? No thanks. He makes Magneto and Shaw look like petty school bullies when it comes to super villainy.
Apoc didn't give up his ideas about mutant supremacy and Might Makes Right, the X-Men adopted that.