One thing I'm certain that most of my readers who have children know is this:
Little children LOVE to hear/read/see the same stories or cartoons over and over again.
One of the great joys of my two little ones is to climb up into my lap and ask for a song or a cartoon. Yes, they absolutely love to watch or listen to these on YouTube while asking lots of questions (cue the 3 year old's recursive 'why'. The fare they prefer tends towards 1930s-1960s cartoons and music from the either the 1970s and 1980s or from classical sources.
Just as a way of amusing myself, I decided to play around a bit with the comments, likes, and comment up/down system on said site. It turns out that likes are several order of magnitudes smaller than views, and that comment ratings are several orders of magnitude smaller still. It also turns out that the 'top comments' are sitting there right in the bottom field of view of the typical watcher.
It is also true that a lot of these videos on youtube have not hundreds, or thousands of hits, but rather millions and tens of millions.
What's more, the top comments are pathetically easy to hijack. There's not even an implied social convention against non sequitur. You can toss a 'Free Zimmerman!' into the middle of, say, a comment section on a Pat Benatar video and if people agree/like it, they'll upvote it. There doesn't appear to be a self-appointed policing force regarding staying 'on topic' at all.
In addition, there appears to be an aging policy on the top comments---they aren't determined solely by the highest number of upvotes minus downvotes (only the result shows, not the number of negatives and positives, so 'discourse poisoning' a la Occidental Dissent isn't even obvious). So you can often dethrone a top comment with way more upvotes than yours. It is also true that there are very few 'Chicago Safeguards' in the voting algorithm, so you can vote early and often--I suspect some sort of session cookie is being used. If you downvote everything above you and get 3-4 positive net upvotes that are fresh votes, you can take control of a billboard viewed by millions.
Why is this important? Well, people see the top comments and assume that they reflect the feelings of lots of people like themselves. They then slot them into their brain as potential norms that they can conform towards. There's no reason that the Left should have a monopoly on this sort of manipulation. If you like, you can even make the comments somewhat relevant, for instance, on an old 1970s or 80s video from a live performance, you can comment on how much thinner and more attractive the prole women of that era were, and make an implied connection to how diversity has spoiled that. Of course this tactic won't work forever, but it is just that, a tactic, and a useful one at that.