The answer is: They were all left-handed

Jdg 20:16

In the whirlwind of the battle described in Judges 20, the 700 left-handed Benjamite slingers stand out as remarkable figures. Their unique skill reflects not just personal mastery, but also a curious historical quandary—the balance of being left-handed in a predominantly right-handed world. Their being left-handed in warfare pointed to an innovative advantage; armies monolithically trained the majority into right-handed combat techniques, leaving left-handers to flank their opponents disorientingly. It's a classic underdog moment if there ever was one!

The reference to "left-handed" soldiers also echoes through scripture, where left-handed figures pop up seeking to defy norms. Eglon’s assassination in Judges 3 features Ehud, a left-handed judge who invokes surprise to achieve victory against Moab. This hints at ingenuity often overlooked in conventional military strategy.

Interestingly, historically, many left-handed individuals have made significant contributions in various fields despite the challenges they face in a right-handed society. Even linguistically, "sinistral" brings to mind "sinister," originally a Latin term for left; a fascinating bit of etymology reflecting societal attitude towards handedness.

These 700 skilled warriors symbolize how God's hand isn’t tied by convention; it defies expectations to achieve His plans. Thus, it's essential to acknowledge that in the Anderson of scriptures, strategic thinking, reliability, and God-given abilities can often defy our perceived norms of effectiveness. The unconventional is sometimes the very channel through which deliverance flows.