Youtube previously banned hacking demonstration videos, and his content might have got caught up in it. It could have been an accident, but even without evidence, one can't help but hypothesize he browsed or engaged with the wrong kind of ideas, or the wrong kind of people were interested in what he did and got associated with that traffic, triggering a cancellation. Conspiracy? Maybe, it doesn't take much to speculate on that conclusion, and there is enough mistrust in tech platforms right now that such a view would just be a product of the where their brands are. Youtube's service, their rules. They have the discretion to disappear peoples content for any reason, but it's worth considering that dumb stuff like this is a multiplier for reinforcing peoples negative views of their service. It's not a question of whether this person was arbitrarily cancelled, it's whether that's what everyone else thinks.

Would you launch, invest in, or run a business that depended on Youtube? If there is hesitation, that's a problem with the platform's brand. In an economics sense, it's becoming an inferior product - something you substitute away from as soon as you can afford to. There is still lots of money to be made in inferior products, but that does imply a negative inflection point for growth.