Ever wonder why pre-20th century boxers always took that funny-looking fighting stance?

Predominantly during the days of bare-knuckle boxing. It may look silly nowadays, but back then, that was an ideal stance to take during a match. In bare-knuckle boxing, the head wasn't the primary target like it is today, as striking the face bare-fisted can and often would result in injury to one's hand. Because of this, striking the body was the main focus while boxing, so the above stance you see is taken with guarding the body in mind while also keeping their fists up and at the ready. It wasn't until the advent of gloved boxing when targeting the head became the new norm. Far less risk of injury when you're punching someone in the face while wearing a padded glove to absorb any trauma your fist would take punching bare-knuckled. But if the fighters from that back then saw today's usual fighting stance of guarding the head, they might just think that looks ridiculous.