Probably because they've been using known and unsafe practices for a long time, and we're giving them a bunch of our data. Seems like "propaganda" is the wrong term, and "legitimate concern and skepticism" would be the correct term.
Think it is pretty clear there is. Now for what purpose and whom? Is it to create more distrust in the US? Is it to try to get us to destroy ourselves from within?
Some of it might be related to partisan politics, in which these organization play an increasingly important role. Some of it might be competitors or would-be competitors. A pretty fair bit, especially here, is likely to be sour grapes and tall poppy syndrome. Some people feel they deserve those billions, and are extremely bitter toward those who actually succeeded.