The President of the United States has explicitly said in the past that he will call any media or story he doesn't like "fake news" as it will damage them in the eyes of his supporters, making any story that is not positive for him into a "fake news" fabricated partisan attack. At the same time, he will demagogue fake claims regarding a "migrant caravan" being full of middle eastern terrorists and gang members who may or may not be funded by George Soros coming to "invade" our country.
The package discovered today does appear to have been sent by the same ardent supporter of the President who liked to repeat the same "fake news"/"enemy of the people" rhetoric. The synagogue terrorist cited the literal fake news about the caravan being funded by Jews to attack America.
This sort of rhetoric has power. The bomber seems to have been largely apolitical before 2016, and then his social media streams changed to nearly all political posts. There is a portion of the media/social media that deliberately stews their consumers in hatred, paranoia and conspiracy mindset. Senators and Congressmen have repeated the same claims about Soros secretly funding everything, trying to "invade" our local governments.