Well. That's your issue. Generally you are going to find two things on YouTube: Pirated material and crap teaching from people who don't know what they are talking about.
The vast majority of videos with quality teaching are pirated, so watching those is basically being complicit in intellectual property theft.
The ones that are not pirated are generally people who don't really perform much, or who are pretty bad at it. They reveal methods on YouTube because they have no other way to get the attention they crave. If they were any good, they'd get the attention from the audiences.
The other option, which is fairly rare, is generally people who are decent performers and can actually teach something clearly - they are almost always teaching someone else's material, which is also slimy.
Ever wonder why inexpensive magic often sucks and good magic is really expensive? That's why. A lot of the cheap stuff is either half-formed products that someone put out because they think selling tricks makes them famous, or it's throw-away tricks from good performers who just want to keep the royalty checks rolling in. The expensive stuff is expensive because if you pay a lot for something you are far less likely to reveal it causally. It's basically creating a price wall to keep stuff secret.