Jesus you people are seeing way to deeply into this, along with your own personal biases against DBZ and Linkin Park. I mean, do you honestly expect your opinions on this to matter if its clear you already hate dbz and Linkin Park anyway.
The reason for the constant Dbz/Linkin Park vids is really simple. Theyre just a really obvious and easy match. Most music vid makers are not pros, theyre beginers, and putting Dbz and Linkin Park together is something that can be really easily done by beginer. This is also why Dbz/Linkin Park vids suck so much, theyre all done by beginers. Also, beginers at music vids are most likely new to anime has well and less likely to have a huge amount of anime they own to go through for footage. No problem, Dbz is on CN every day, dont gotta worry you havent had time to by anything other than you Linkin Park album your parents probably bought you.
Stop being so condesending towards all these people just trying to start out and get some experience. When you try and learn something new, you dont instantly go for the hardest level, you start out simple, Dbz and Linkin Park together is very simple, very easy to time and match emotion and such. I know ive seen people go from producing crappy dbz/Linkin Park vids to making vids that will be remembered fondly for a long time in less then a year or two of experience making vids. Point is, give these people a break, they'll get better in time, especailly with all the great vid makers out there now to learn from now.