In general I believe that copyright is too strict and borderline ridiculous. Every mainstream artist throws a fit about there music being "stolen" or "pirated." I just feel like so many people are over sensitive about there own creations. Many lawsuits have been filed against Dj's and other musicians who remix things simply because the artist or more likely the record company feels cheated out of a dollar and twenty-nine cents. Many of the people using the music others create are not doing it for profitable gain. They do it just to do it and let the listeners enjoy it with worries about profit. There are too many double standards in what constitutes fair use or not these days.
If you aren't receiving money for it it is not a copyright violation. It's only copyright infringement if the person redistributes the work as entirely there own. But it's also hard to determine who will care and who won't. There are many rich musicians who get angry if people pirate there music or use it in personal projects of there own. Then there are other artists who only care about there fans getting a hold of there music and don't care, or sometimes even encourage downloading there music for free or remixing it or whatever.
There are too many exceptions to the rules when it comes to copyright laws and personally i feel they need to be changed. It's kind of just one big confusing contradiction and people wouldn't have to fear lawsuits simply because they wanted to upload a mashup to youtube. People aren't always trying to cheat the artist out of anything. Just trying to combine pieces in order to make something new. Is remixing and pirating wrong? In the eyes of the law yes, but as for the real answer to that question we might actually never know