Yes, I expect many of the mixed would have voted left of mixed wasn't an option, I would have done.I fear the vote will prove inconclusive. Perhaps it was a mistake to put Mixed as an option. What I am reading is a lot of people who might have been classed as Left handed have figured ways to work with both and have voted in mixed.
I would normally say I'm left handed, as I write left handed. I voted mixed as I do many other things right handed. If it's something new to me I often don't know if I'll do it right or left handed until I try to do it. Somewhat strangely I'll paint as an artist with my left hand but decorate with my right hand. At some point I'll switch to doing fine detail with my left.