Because it's easy when you don't let facts block you. Spread lie number 1 on Monday morning, lie number 2 in the afternoon, lie number 3 the next day, and do that for years and decades.

Whenever someone spends the time, and it takes a long time, to correct you, laugh, mock them, spew a few more lies.

And it's easy to do when the rich, the owner class side with you, because they buy newspapers, websites, ads, which you can't do if you lean left because acquiring money at all cost is not a priority of left wing people.