First, let me quickly say I am not offended that someone says it's stealing. Standing up to say the moral thing is important and I support that.
Second, let me quickly say I am not sure using these samples is either immoral or unethical. How can I say this? Well it may be rationalizing but I'm going to let the copyright holder and youtube deal with that issue. As they are videos on youtube's site, they are published for viewing and use by the public. This is youtube's view. And their view goes on to be, the videos will be removed when they are asked by the copyright holder. When this happens the issue is resolved, as is any moral, ethical, legal question about them.
I have not copied the videos, nor have I used them in class (as of yet -- and wouldn't until next semester at the earliest). I will continue to ponder the questions/points which you guys have raised. I don't consider myself to have stolen anything because I have not copied anything. In class, we could just view the videos online. As an analogy, I don't have to own the Mona Lisa to enjoy it or to use it for teaching art.
I'm not looking to profit financially from the videos, although one could say that I am because I'm being paid to teach and the videos would be part of that, but I don't think that argument holds much weight. In a sense - and maybe too broad a sense - I think the videos fall into "fair use" for education.
As I've said, I have a while to ponder this. I am a strong opponent to illegal copying of software/music. Why I think this is somehow different is something I'll have to work out in my mind. It may be the issue is resolved by others before then.
Barry