One reason might be in the other question this Huffington Post/YouGov poll asked: "To the best of your knowledge, would you say it is currently legal or illegal under federal law to fire someone for being gay or lesbian?" Just 14 percent of people answered correctly that workplace discrimination against LGBT people is legal under federal law, while 62 percent believed that it's illegal. So some of these people may have answered the question about whether there should be a law against job discrimination thinking there already was. In fact, this isn't the first poll showing that Americans believe anti-gay workplace discrimination is already illegal: A 2011 poll found that nine out of 10 voters thought there was a federal law against discrimination.
The Senate has passed the Employment Non-Discrimination Act, but House Speaker John Boehner won't even let it come up for a vote despite widespread support (the 76 percent in this poll who say it should be illegal to fire someone over their sexual orientation is more in line with other polling than is the 50 percent who say they favor a law prohibiting discrimination). And, unfortunately in this case, people believing it is and should be the law doesn't make it so.