How much damage are single issue voters doing to the democratic process and usa?

they will promote, support, and vote for anyone who champions their cause, regardless of whatever other weird causes that candidate may believe in. i have personally observed people who have not voted in years who will register to vote, carry signs, attend rallies, and vote for a candidate because someone at their kid's school, their church, or a social event handed them a computer generated flyer saying this guy believes in their pet peeve.