Despite what his sly smirk and penchant for smooth '80s jams might say, Star-Lord is a bad guy. Some Peter Quill fans may cite Star-Lord's messed-up backstory as the reason behind his less-than-savory antics, but some of his actions go beyond having a troubled childhood. Star-Lord is the real villain of Infinity War, and it's not the only time he has acted like a Big Bad.
Even though he's the face of a major cinematic and comic book franchise, Star-Lord pretty much acts like a villain in every situation. If there's a wrong move to make, he'll make it, and he won't apologize. A number of Star-Lord facts perfectly illustrate how Peter Quill is problematic at best, and an out-and-out villain at worst. Whether or not these awful things Star-Lord has done change the way you watch Guardians of the Galaxy is up to you.
Let's address the elephant in the room: Peter Quill's most villainous moment ever is the part he plays in killing half of the MCU in Infinity War. In an effort to rid Thanos of the Infinity Gauntlet, Doctor Strange, Iron Man, Mantis, Drax, Spider-Man, and Star-Lord hatch a tag-team plan. While Mantis has the Mad Titan under a hypnotic daze, Star-Lord learns that Thanos killed Gamora to get his hands on the Soul Stone.
All Star-Lord needed to do was slip the glove from Thanos's hand and call it a day. Instead, he punches Thanos in the face, waking him up in the process. Star-Lord may have had noble intentions, but it's our actions that define us, and this is quite the antihero move.
As far as villain resumes go, killing an entire planet's worth of people is one of the first things that's listed under "Unique Skills." Peter Quill, like many baddies before him, wipes entire civilizations out of existence and chalks it up to the greater good.
While fighting the Fallen One, a former henchman for Galactus, Star-Lord and his ship discover they can weaken their enemy by destroying a planet. Instead of figuring out a better way to take down their foe, Star-Lord and his sentient ship send 35,000 people to their deaths.
Admittedly, Earth-10011, or the "Cancerverse," isn't a great place to live in the first place. But just because it's an awful alternate universe that's taken on a particularly Lovecraftian look due to its inability to let anything die doesn't mean it deserves to be destroyed. When the Cancerverse begins to leak into the 616 continuity, Star-Lord puts a crew together that includes Silver Surfer and Thanos with one mission: bring death to the alternate universe.
The group succeeds in their mission after Thanos allows himself to be killed, an act that brings Earth-616's manifestation of Death to Earth-10011. Once in the alternate, deathless universe, Death becomes insatiable and kills everything. The inhabitants of the alternate universe may be "bad," but Peter Quill is just as bad, if not worse, for setting out to kill them simply for existing.
The Annihilation War is a dense and complex saga that follows an alien race called the Phalanx as they try to take over the universe. The Phalanx are a cybernetic race of creatures who infect other races in an attempt to take them over and cause general destruction.
One of the easiest ways to avoid dealing with them is to eschew technology. Peter Quill all but lays out the welcome mat for the cyber-race when he invites the Spaceknights to update the Kree homeworld's security in the prologue to Annihilation: Conquest.
Unbeknownst to Star-Lord, the Spaceknights were infected with a Phalanx techo-virus, and after they interface with the Kree defense systems, all hell breaks loose. With the help of Thanos and Galactus (of all people), a very long and drawn-out battle comes to an end. All the death and destruction could have been avoided if Peter Quill wasn't involved.