"Why don't atheists want to be Christian when Jesus said His yoke is light?"
Because it's a free country and I don't have to be Christian if I don't want to.
"Matthew 12:30, "For the yoke I will give you is easy, and the load I will put on you is light.""
Yokes are for oxen, not people.
"Under the Old Law of Moses, there was so much stuff you had to do to be right that it just wasn't possible. Now the Man Jesus came along and said to follow Him, because all He said was to have only 1 God and Love thy neighbor as thyself, pretty easy no?"
And what's so impossible about simply respecting others, helping those who need it and living a clean, honest life? I do it every day, I don't need some cosmic babysitter following me around. Besides, most atheists adhere to that "love thy neighbor" bit a lot better than many christians do. Our minds aren't clouded by all the prejudice and propaganda you fundies are are so gullibly falling for, so we can truly see our neighbors as neighbors, and not witnessing fodder.
"So why do some think it's hard to believe that?"
Because I've been there and I've seen that it's bullshit.