I think a popular cartoon anime figure often has an appealing personality. It could be brave, kind, or have a sense of humor. Also, the way it looks visually, like its outfit and hairstyle, can draw people in. Sometimes, if it's associated with a really engaging story or plot, that makes it more popular too.
It could be highlighting his policy positions or maybe satirizing certain aspects of his political image. Hard to say for sure without seeing the specific cartoon.
Common techniques in political cartoons include exaggeration, satire, and symbolism. These are used to make a point or criticize a situation in a visually impactful way.