Youtube and social media form a two edged sword. The internet can be a tremendously powerful tool for spreading messages, but it's also really good at creating echo chambers and an inflated sense of self-importance, especially among those who have large followings.
There's now also money to be made depending on how you can leverage your views and followers, whether through ad revenue, donations, and overt or covert sponsorship deals. The combination of these monetary opportunities along with the quasi-celebrity aspect of having large followings can attract, feed, or even create some really devious, dishonest, and egocentric people.
When the image of someone who is using their e-fame for profit is threatened, their revenue stream and their followings are also threatened. This can lead to some pretty shameful drama in the form of fighting and infighting. This drama also attracts its own attention, and since there's money to be made simply by leveraging that attention, it's not surprising that it becomes a business model for some to attack others. This isn't just a problem in the vegan community, but it seems to have reached disproportionate levels within it.
There's another area where this seems to have been going on a lot longer. It's in the social justice, atheist, and religious sectors of youtube and social media. They have been full of infighting and attack videos against other prominent figures. Even Richard Dawkins himself has fallen victim to this problem.
So what do social justice, religion, veganism, and atheism to some extent have in common? They all involve spreading a prescriptive moral message, whether or not that message itself is ultimately correct and helpful or incorrect/unverifiable and harmful. Some of you may balk at the idea that there is a prescriptive moral message to atheism, and you'd be technically correct. By itself it is simply a lack of belief and doesn't need to go farther, however its proponents often argue that it is an ethically and philosophically superior position to holding many of not most or all religious beliefs, and that people should be atheists. I do tend to agree, but I digress. The point is that all these "isms" can offer an opportunity to get behind a cause which is presented as helpful and well-meaning. This also affords the opportunity for charlatans to pose themselves as paragons of goodness. There's an old term for that in Christianity: a wolf in sheep's clothing.
The wolves have come to veganism, and they have done it through youtube and social media.
The core message of veganism is simple enough. If you don't need to cause or support the suffering and death of animals through your purchases and consumption, then it's better not to do so. Therefore one ought to take care to minimize or eliminate their contribution to animal exploitation when and where they can. It's an extension of a basic moral edict: try to avoid harming others if you can. That's it. The message itself can and should stand on its own, separate from any one person or group.
That's all I wanted to say.