The main skills you need as a DJ (and somewhat as a producer) is: Knowing what to play next.
This sounds simple, but honestly is the hardest skill, as it is hard to learn. It involves such things as passion and love for music, but also abilities to read the crowd and the love to entertain people.
Combine this with considerable knowledge about music theory (in many cases no less than a composer would need) if you want to create perfectly keyed and harmonic sets.
Hence it is a hugely creative way of expressiing yourself.
Why some poeple do not get this is actually 2 things:
1. The main skill (playing the next song) can be done by anyone from a technical standpoint. The basic skills to beatmatch etc. can be learned in a week. So it looks like you are not doing much to some poeple and many musicians will diss you as you did not need years to perfect your technical skills. They overlook the parts I wrote above.
2. There are lots of “bad” DJs, that are only in it for a quick way to make cash (which they fail in mostly) and who can easily be replaced by iTunes Genius playlists.
These 2 things combined sometimes make people think that DJs are “worth less” than other musicians or composers. Where I have found sometimes I know more about music theory than the avarage guitar player, that most of them cannot even read music, as they use their tab system and they also only play what others wrote. So while yes they are to be congratulated to master the technical skill of playing guitar, their creative expression is sometimes less than mine as a DJ. (and I play 3 instruments, so I can relate)
