Picking on someone vastly weaker than you (especially while they're already getting beat up by somebody else) doesn't make you look strong, it mostly just makes you look like an asshole, and probably an asshole who is too scared or too weak to go after somebody who can actually fight back.

> it mostly just makes you look like an asshole

This is true, but only for a certain percentage of the US population. Large swaths of this country think that picking on our weaker neighbors evidence of our strength