2. They have a commercial reason to cancel these videos. Maybe they think the use of these drugs is risky, and gives their website an unsavory reputation. That hurts their brand (and potentially their bottom line). This is not unlike a TV show canceling a successful show when it's star actor becomes embroiled in controversy.
Number 2, agreed, we in fact know it can only be censorship (and not competing viewership) that drives the decision. That's my whole point.
https://www.backblaze.com/blog/hard-drive-cost-per-gigabyte/
https://www.statista.com/statistics/259477/hours-of-video-up...
As far as I can tell, YouTube video content is growing exponentially, and hard drive costs are dropping linearly.
Storage and network charges are already pennies per terabyte-day. So currently and in the forseeable future, YouTube's costs will probably be administrative.
And that's all beside the point. There's not hard 24-hour one-channel limit to what YouTube can 'broadcast'. So their model is completely unlike a traditional TV station. So that analogy is flawed. So we can conclude, YouTube's decision to show (or not show) anything is based on completely different criterion. Pedantry notwithstanding.
1a. Youtube has other expenses besides hard drives. Bandwith. Server infrastructure. Employee salaries. To name a few.
2. It's not censorship. It's editorial judgement. Are you saying websites should be forced to host opinions they don't agree with? There is no "fairness doctrine" for sites like youtube.