I think it's more about wilful ignorance than truth. I saw a video the other day with a US student protesting a speaker at his uni, and saying how he thought that some political violence could be useful. He then went on to admit he didn't know what the speaker looked like, nor what they believed, nor had he ever seen or heard anything they'd done. He'd just seen a poster saying that this person was bad, that was enough for him.
I've thought for a long time that when the generation that fought in the war, or even grew up in it, has died out, that's when idiots like this student will be free to make something terrible rise. Fight for freedoms like speech while you can.