Most westerner's views of Saudi Arabia are very much influenced by actions the country's government has previously taken [1]. It isn't so much propaganda, as much as it is the government, lead by MSB, taking actions that greatly offends our sensibilities, most notably the killing of Jamal Khashoggi among other smaller incidents and snafus which have made Saudi Arabia and MSB look horrible.
[1] https://en.wikipedia.org/wiki/Jamal_Khashoggi