Why does the liberal media continue to lie about threats and attacks on Congressmen?

The liberal media keeps up it's socialist rhetoric by claiming Democratic Congressmen and Senators have been threatened after voting on Obamacare but offer no evidence that anyone tied to the Republican party is responsible for whatever has happened, which is very little if anything at all. Is it the liberal's plan to rile up opponents of Obamacare and stoke the fire to incite violence to make themselves look like victims? They have done it before.