Several have pointed out that the only references to left-handed people in the Bible are to people from the tribe of Benjamin, whose name ironically means, son of my right hand. The refernces are positive not pejorative.
Judges 3:15 Ehud Again the Israelites cried out to the LORD, and he gave them a deliverer - Ehud, a left-handed man, the son of Gera the Benjamite. The Israelites sent him with tribute to Eglon king of Moab.
Judges 700 Benjaminite specialists 20:16 Among all these soldiers there were seven hundred select troops who were left-handed, each of whom could sling a stone at a hair and not miss.
1 Chronicles 12:1, 2 Relatives of Saul who served David These were the men who came to David at Ziklag, while he was banished from the presence of Saul son of Kish (they were among the warriors who helped him in battle; they were armed with bows and were able to shoot arrows or to sling stones right-handed or left-handed; they were relatives of Saul from the tribe of Benjamin):