That’s 47% that said they would consider voting for a socialist. It doesn’t mean they would. Heck, I consider all candidates on the ballot regardless of party, but that doesn’t mean I’m going to vote for them. Under consideration and voting for are two different things. I suppose the good news there is about half of all Americans wouldn’t rule out voting for a socialist. The bad News, a bit over half wouldn’t even consider it.
But like everything else, it probably boils down to who the candidates are. I would have voted for Sanders before I’d vote for Hillary Clinton. Now if I don’t like either one of the major party candidates, I vote third party to officially register my objections to both. No voting for the lesser evil or the candidate I want to lose the least. If I want both to lose, I vote that way via third party.