The statements "vaping isn't good for you" and "vaping is a lot better than smoking" do not conflict with another; they can both be true.
Whether vaping is an improvement or not depends on what you were doing before. If you were smoking before and are substituting cigarettes for vaping, you hurt yourself a lot less and it's an improvement.
If you weren't smoking before (the case for most teens for example) and would start to vape, you'd be hurting yourself significantly more than before.
You should be advocating to never touch a vape (or cigarette) to non-smokers and to try vaping to get out of smoking addiction to smokers.
Depends on how many other users are using the same proxy. If you host piped for yourself using your home internet connection, Google will absolutely know who is watching the video.