But now you are missing the point.
Your point was that you didn't consider Magneto and Loki real villains, more like "traitors", not legitimate villains.
Loki killing 80 people, bringing war to Asgar and earth, betraying his father twice, taking a guy's eye out and torturing him....makes Loki a villain, not an anti hero or a rogue.
Magneto is also a cold blooded killer who always betrays the heroes and has also taken plenty of lives. He's not Jack Sparrow...Magneto is a villain who hates humans.
The death count counts. It might not make them all time great villains in your opinion, but they're definitely villains.