I tend to avoid the word "propaganda" where I think the term "one-sided" would qualitatively suffice, but those YouTube videos are fairly close to the definition of propaganda. The series is essentially one of the common hate-driven cherry-picking machines the internet is constructed out of. This is coming from me, a non-vegan who thinks that adequate nutrition is much more difficult for vegans, and therefore by the very laws of statistics, if that assumption is true, then vegans are in fact on average less well-nourished compared to people with adequate access to food and no dietary restrictions.