[betwixthewires]

I can tell you why, it's because it is a very prominent example of a blatant bald faced lie left as is to propagandize naive people who won't actually look into things themselves and delegate that role to Snopes.

If Trump makes a huge number of false statements it should attract the attention of everyone. People that delegate their own critical thinking to an entity claiming to be unbiased and informed in doing it for them are going to be misled one way or another.